Issue #24585: Enables build-to-build upgrades that preserve settings.

Rather than using Burn "Persisted" variables we now add registry keys for each added feature. These can be detected by the installer regardless of which version installed them, and we use this for Modify and Upgrade. In particular, Upgrades can't access the Persisted variables, but can find well-known registry keys.
There are also some changes to the bootstrap app to properly handle upgrades.
Finally, a few minor improvements to the Windows build to keep things tidier.

33 files changed, 456 insertions, 135 deletions

diff --git a/PCbuild/build.bat b/PCbuild/build.bat
index 3f8e231df0..17f8686b42 100644
--- a/PCbuild/build.bat
+++ b/PCbuild/build.bat
@@ -25,16 +25,17 @@ set verbose=/nologo /v:m
 set kill=

 

 :CheckOpts

-if '%1'=='-c' (set conf=%2) & shift & shift & goto CheckOpts

-if '%1'=='-p' (set platf=%2) & shift & shift & goto CheckOpts

-if '%1'=='-r' (set target=Rebuild) & shift & goto CheckOpts

-if '%1'=='-t' (set target=%2) & shift & shift & goto CheckOpts

-if '%1'=='-d' (set conf=Debug) & shift & goto CheckOpts

-if '%1'=='-e' call "%dir%get_externals.bat" & shift & goto CheckOpts

-if '%1'=='-m' (set parallel=/m) & shift & goto CheckOpts

-if '%1'=='-M' (set parallel=) & shift & goto CheckOpts

-if '%1'=='-v' (set verbose=/v:n) & shift & goto CheckOpts

-if '%1'=='-k' (set kill=true) & shift & goto CheckOpts

+if '%~1'=='-c' (set conf=%2) & shift & shift & goto CheckOpts

+if '%~1'=='-p' (set platf=%2) & shift & shift & goto CheckOpts

+if '%~1'=='-r' (set target=Rebuild) & shift & goto CheckOpts

+if '%~1'=='-t' (set target=%2) & shift & shift & goto CheckOpts

+if '%~1'=='-d' (set conf=Debug) & shift & goto CheckOpts

+if '%~1'=='-e' call "%dir%get_externals.bat" & shift & goto CheckOpts

+if '%~1'=='-m' (set parallel=/m) & shift & goto CheckOpts

+if '%~1'=='-M' (set parallel=) & shift & goto CheckOpts

+if '%~1'=='-v' (set verbose=/v:n) & shift & goto CheckOpts

+if '%~1'=='-k' (set kill=true) & shift & goto CheckOpts

+if '%~1'=='-V' shift & goto Version

 

 if '%platf%'=='x64' (set vs_platf=x86_amd64)

 

@@ -50,3 +51,9 @@ rem Passing %1-9 is not the preferred option, but argument parsing in
 rem batch is, shall we say, "lackluster"

 echo on

 msbuild "%dir%pcbuild.proj" /t:%target% %parallel% %verbose% /p:Configuration=%conf% /p:Platform=%platf% %1 %2 %3 %4 %5 %6 %7 %8 %9

+

+@goto :eof

+

+:Version

+rem Display the current build version information

+msbuild "%dir%python.props" /t:ShowVersionInfo /v:m /nologo %1 %2 %3 %4 %5 %6 %7 %8 %9

diff --git a/PCbuild/python.props b/PCbuild/python.props
index 1431ddcfe7..857b8f8ee7 100644
--- a/PCbuild/python.props
+++ b/PCbuild/python.props
@@ -42,7 +42,9 @@
     
     <!-- Full path of the resulting python.exe binary -->
     <PythonExe Condition="'$(PythonExe)' == ''">$(BuildPath)python$(PyDebugExt).exe</PythonExe>
-
+  </PropertyGroup>
+  
+  <PropertyGroup Condition="'$(OverrideVersion)' == ''">
     <!--
     Read version information from Include\patchlevel.h. The following properties are set:
     
@@ -70,7 +72,40 @@
     <ReleaseLevelName Condition="$(_ReleaseLevel) == 'ALPHA'">a$(ReleaseSerial)</ReleaseLevelName>
     <ReleaseLevelName Condition="$(_ReleaseLevel) == 'BETA'">b$(ReleaseSerial)</ReleaseLevelName>
     <ReleaseLevelName Condition="$(_ReleaseLevel) == 'GAMMA'">rc$(ReleaseSerial)</ReleaseLevelName>
+  </PropertyGroup>
+  
+  <PropertyGroup Condition="'$(OverrideVersion)' != ''">
+    <!--
+    Override the version number when building by specifying OverrideVersion.
+    For example:
+    
+        PCBuild\build.bat "/p:OverrideVersion=3.5.2a1"
     
+    Use the -V option to check your version is valid:
+    
+        PCBuild\build.bat -V "/p:OverrideVersion=3.5.2a1"
+          PythonVersionNumber: 3.5.2
+          PythonVersion:       3.5.2a1
+          PythonVersionHex:    0x030502A1
+          Field3Value:         2101
+    
+    Note that this only affects the version numbers embedded in resources and
+    installers, but not sys.version.
+    -->
+    <MajorVersionNumber>$([System.Text.RegularExpressions.Regex]::Match($(OverrideVersion), `(\d+)\.(\d+)\.(\d+)((a|b|rc)(\d))?`).Groups[1].Value)</MajorVersionNumber>
+    <MinorVersionNumber>$([System.Text.RegularExpressions.Regex]::Match($(OverrideVersion), `(\d+)\.(\d+)\.(\d+)((a|b|rc)(\d))?`).Groups[2].Value)</MinorVersionNumber>
+    <MicroVersionNumber>$([System.Text.RegularExpressions.Regex]::Match($(OverrideVersion), `(\d+)\.(\d+)\.(\d+)((a|b|rc)(\d))?`).Groups[3].Value)</MicroVersionNumber>
+    <ReleaseLevelName>$([System.Text.RegularExpressions.Regex]::Match($(OverrideVersion), `(\d+)\.(\d+)\.(\d+)((a|b|rc)(\d))?`).Groups[4].Value)</ReleaseLevelName>
+    <_ReleaseLevel>$([System.Text.RegularExpressions.Regex]::Match($(OverrideVersion), `(\d+)\.(\d+)\.(\d+)((a|b|rc)(\d))?`).Groups[5].Value)</_ReleaseLevel>
+    <ReleaseSerial>$([System.Text.RegularExpressions.Regex]::Match($(OverrideVersion), `(\d+)\.(\d+)\.(\d+)((a|b|rc)(\d))?`).Groups[6].Value)</ReleaseSerial>
+    <ReleaseSerial Condition="'$(ReleaseSerial)' == ''">0</ReleaseSerial>
+    <ReleaseLevelNumber>15</ReleaseLevelNumber>
+    <ReleaseLevelNumber Condition="$(_ReleaseLevel) == 'a'">10</ReleaseLevelNumber>
+    <ReleaseLevelNumber Condition="$(_ReleaseLevel) == 'b'">11</ReleaseLevelNumber>
+    <ReleaseLevelNumber Condition="$(_ReleaseLevel) == 'rc'">12</ReleaseLevelNumber>
+  </PropertyGroup>
+  
+  <PropertyGroup>
     <PythonVersionNumber>$(MajorVersionNumber).$(MinorVersionNumber).$(MicroVersionNumber)</PythonVersionNumber>
     <PythonVersion>$(MajorVersionNumber).$(MinorVersionNumber).$(MicroVersionNumber)$(ReleaseLevelName)</PythonVersion>
     <PythonVersionHex>$([msbuild]::BitwiseOr(
@@ -110,7 +145,7 @@
   <Target Name="ShowVersionInfo">
     <Message Importance="high" Text="PythonVersionNumber: $(PythonVersionNumber)" />
     <Message Importance="high" Text="PythonVersion:       $(PythonVersion)" />
-    <Message Importance="high" Text="$([System.String]::Format(`PythonVersionHex:    0x{0:x}`, $([System.UInt32]::Parse($(PythonVersionHex)))))" />
+    <Message Importance="high" Text="PythonVersionHex:    0x$([System.UInt32]::Parse($(PythonVersionHex)).ToString(`X08`))" />
     <Message Importance="high" Text="Field3Value:         $(Field3Value)" />
   </Target>
 </Project>
diff --git a/Tools/msi/build.bat b/Tools/msi/build.bat
index 1dc05c3997..c135b63d21 100644
--- a/Tools/msi/build.bat
+++ b/Tools/msi/build.bat
@@ -8,10 +8,10 @@ set BUILDX64=
 set BUILDDOC=

 

 :CheckOpts

-if "%1" EQU "-h" goto Help

-if "%1" EQU "-x86" (set BUILDX86=1) && shift && goto CheckOpts

-if "%1" EQU "-x64" (set BUILDX64=1) && shift && goto CheckOpts

-if "%1" EQU "--doc" (set BUILDDOC=1) && shift && goto CheckOpts

+if "%~1" EQU "-h" goto Help

+if "%~1" EQU "-x86" (set BUILDX86=1) && shift && goto CheckOpts

+if "%~1" EQU "-x64" (set BUILDX64=1) && shift && goto CheckOpts

+if "%~1" EQU "--doc" (set BUILDDOC=1) && shift && goto CheckOpts

 

 if not defined BUILDX86 if not defined BUILDX64 (set BUILDX86=1) && (set BUILDX64=1)

 

diff --git a/Tools/msi/bundle/Default.thm b/Tools/msi/bundle/Default.thm
index d5e1969977..0c79dd50c0 100644
--- a/Tools/msi/bundle/Default.thm
+++ b/Tools/msi/bundle/Default.thm
@@ -21,13 +21,24 @@
 
         <Text X="185" Y="50" Width="-11" Height="50" FontId="3" TabStop="yes">#(loc.InstallMessage)</Text>
 
-        <Button Name="InstallJustForMeButton" X="175" Y="101" Width="-11" Height="129" TabStop="yes" FontId="3" HexStyle="0xE">#(loc.InstallJustForMeButton)</Button>
+        <Button Name="InstallButton" X="175" Y="101" Width="-11" Height="129" TabStop="yes" FontId="3" HexStyle="0xE">#(loc.InstallButton)</Button>
         <Button Name="InstallCustomButton" X="175" Y="241" Width="-11" Height="59" TabStop="yes" FontId="3" HexStyle="0xE">#(loc.InstallCustomButton)</Button>
 
         <Checkbox Name="PrependPath" X="185" Y="-13" Width="-100" Height="20" TabStop="yes" FontId="3">#(loc.ShortPrependPathLabel)</Checkbox>
 
         <Button Name="InstallCancelButton" X="-11" Y="-11" Width="75" Height="23" TabStop="yes" FontId="0">#(loc.CancelButton)</Button>
     </Page>
+    <Page Name="Upgrade">
+        <Text X="185" Y="11" Width="-11" Height="32" FontId="1" DisablePrefix="yes">#(loc.InstallUpgradeHeader)</Text>
+        <Image X="0" Y="0" Width="162" Height="352" ImageFile="SideBar.png"/>
+
+        <Text X="185" Y="50" Width="-11" Height="50" FontId="3" TabStop="yes">#(loc.InstallUpgradeMessage)</Text>
+
+        <Button Name="InstallUpgradeButton" X="175" Y="101" Width="-11" Height="129" TabStop="yes" FontId="3" HexStyle="0xE">#(loc.InstallUpgradeButton)</Button>
+        <Button Name="InstallUpgradeCustomButton" X="175" Y="241" Width="-11" Height="59" TabStop="yes" FontId="3" HexStyle="0xE">#(loc.InstallUpgradeCustomButton)</Button>
+
+        <Button Name="InstallCancelButton" X="-11" Y="-11" Width="75" Height="23" TabStop="yes" FontId="0">#(loc.CancelButton)</Button>
+    </Page>
     <Page Name="SimpleInstall">
         <Text X="185" Y="11" Width="-11" Height="32" FontId="1" DisablePrefix="yes">#(loc.InstallHeader)</Text>
         <Image X="0" Y="0" Width="162" Height="352" ImageFile="SideBar.png"/>
diff --git a/Tools/msi/bundle/Default.wxl b/Tools/msi/bundle/Default.wxl
index 3ecb2faf8e..19ba7eb14b 100644
--- a/Tools/msi/bundle/Default.wxl
+++ b/Tools/msi/bundle/Default.wxl
@@ -21,6 +21,8 @@ Continue?</String>
   <String Id="InstallHeader">Install [WixBundleName]</String>
   <String Id="InstallMessage">Select Install Now to install Python with default settings, or choose Customize to enable or disable features.</String>
   <String Id="InstallVersion">Version [WixBundleVersion]</String>
+  <String Id="InstallUpgradeHeader">Upgrade to [WixBundleName]</String>
+  <String Id="InstallUpgradeMessage">Select Upgrade Now to keep your current settings, or choose Customize to enable or disable features.</String>
   <String Id="ConfirmCancelMessage">Are you sure you want to cancel?</String>
   <String Id="ExecuteUpgradeRelatedBundleMessage">Previous version</String>
   <String Id="HelpHeader">Setup Help</String>
@@ -40,8 +42,8 @@ Continue?</String>
     Logs to a specific file. By default, log files are created in %TEMP%.</String>
   <String Id="InstallLicenseLinkText">[WixBundleName] &lt;a href="#"&gt;license terms&lt;/a&gt;.</String>
   <String Id="InstallAcceptCheckbox">I &amp;agree to the license terms and conditions</String>
-  <String Id="InstallJustForMeButton">&amp;Install Now</String>
-  <String Id="InstallJustForMeButtonNote">[DefaultJustForMeTargetDir]
+  <String Id="InstallButton">&amp;Install Now</String>
+  <String Id="InstallButtonNote">[DefaultJustForMeTargetDir]
 
 Includes IDLE, pip and documentation
 Creates shortcuts and file associations</String>
@@ -49,6 +51,13 @@ Creates shortcuts and file associations</String>
   <String Id="InstallCustomButtonNote">Choose location and features</String>
   <String Id="InstallSimpleButton">&amp;Install</String>
   <String Id="InstallSimpleButtonNote">Uses setting preselected by your administrator</String>
+  <String Id="InstallUpgradeButton">&amp;Upgrade Now</String>
+  <String Id="InstallUpgradeButtonNote">[TargetDir]
+
+Replaces your existing installation without changing settings.
+Select Customize to review current options.</String>
+  <String Id="InstallUpgradeCustomButton">C&amp;ustomize installation</String>
+  <String Id="InstallUpgradeCustomButtonNote">Choose location and features</String>
   <String Id="Custom1Header">Optional Features</String>
   <String Id="Custom2Header">Advanced Options</String>
   <String Id="CustomLocationLabel">Customize install location</String>
@@ -107,4 +116,5 @@ Feel free to email &lt;a href="mailto:python-list@python.org"&gt;python-list@pyt
   <String Id="FailureHyperlinkLogText">One or more issues caused the setup to fail. Please fix the issues and then retry setup. For more information see the &lt;a href="#"&gt;log file&lt;/a&gt;.</String>
   <String Id="FailureRestartText">You must restart your computer to complete the rollback of the software.</String>
   <String Id="FailureRestartButton">&amp;Restart</String>
+  <String Id="FailureExistingInstall">Unable to install [WixBundleName] due to an existing install. Use Programs and Features to modify, repair or remove [WixBundleName].</String>
 </WixLocalization>
diff --git a/Tools/msi/bundle/bootstrap/PythonBootstrapperApplication.cpp b/Tools/msi/bundle/bootstrap/PythonBootstrapperApplication.cpp
index 585f66cd5b..728355930a 100644
--- a/Tools/msi/bundle/bootstrap/PythonBootstrapperApplication.cpp
+++ b/Tools/msi/bundle/bootstrap/PythonBootstrapperApplication.cpp
@@ -47,6 +47,7 @@ enum PAGE {
     PAGE_LOADING,
     PAGE_HELP,
     PAGE_INSTALL,
+    PAGE_UPGRADE,
     PAGE_SIMPLE_INSTALL,
     PAGE_CUSTOM1,
     PAGE_CUSTOM2,
@@ -63,6 +64,7 @@ static LPCWSTR PAGE_NAMES[] = {
     L"Loading",
     L"Help",
     L"Install",
+    L"Upgrade",
     L"SimpleInstall",
     L"Custom1",
     L"Custom2",
@@ -79,10 +81,11 @@ enum CONTROL_ID {
     ID_MINIMIZE_BUTTON,
 
     // Welcome page
-    ID_INSTALL_ALL_USERS_BUTTON,
-    ID_INSTALL_JUST_FOR_ME_BUTTON,
+    ID_INSTALL_BUTTON,
     ID_INSTALL_CUSTOM_BUTTON,
     ID_INSTALL_SIMPLE_BUTTON,
+    ID_INSTALL_UPGRADE_BUTTON,
+    ID_INSTALL_UPGRADE_CUSTOM_BUTTON,
     ID_INSTALL_CANCEL_BUTTON,
     
     // Customize Page
@@ -141,10 +144,11 @@ static THEME_ASSIGN_CONTROL_ID CONTROL_ID_NAMES[] = {
     { ID_CLOSE_BUTTON, L"CloseButton" },
     { ID_MINIMIZE_BUTTON, L"MinimizeButton" },
 
-    { ID_INSTALL_ALL_USERS_BUTTON, L"InstallAllUsersButton" },
-    { ID_INSTALL_JUST_FOR_ME_BUTTON, L"InstallJustForMeButton" },
+    { ID_INSTALL_BUTTON, L"InstallButton" },
     { ID_INSTALL_CUSTOM_BUTTON, L"InstallCustomButton" },
     { ID_INSTALL_SIMPLE_BUTTON, L"InstallSimpleButton" },
+    { ID_INSTALL_UPGRADE_BUTTON, L"InstallUpgradeButton" },
+    { ID_INSTALL_UPGRADE_CUSTOM_BUTTON, L"InstallUpgradeCustomButton" },
     { ID_INSTALL_CANCEL_BUTTON, L"InstallCancelButton" },
 
     { ID_TARGETDIR_EDITBOX, L"TargetDir" },
@@ -191,13 +195,35 @@ static THEME_ASSIGN_CONTROL_ID CONTROL_ID_NAMES[] = {
     { ID_FAILURE_CANCEL_BUTTON, L"FailureCancelButton" },
 };
 
+static struct { LPCWSTR regName; LPCWSTR variableName; } OPTIONAL_FEATURES[] = {
+    { L"core_d", L"Include_debug" },
+    { L"core_pdb", L"Include_symbols" },
+    { L"dev", L"Include_dev" },
+    { L"doc", L"Include_doc" },
+    { L"exe", L"Include_exe" },
+    { L"lib", L"Include_lib" },
+    { L"path", L"PrependPath" },
+    { L"pip", L"Include_pip" },
+    { L"tcltk", L"Include_tcltk" },
+    { L"test", L"Include_test" },
+    { L"tools", L"Include_tools" },
+    { L"Shortcuts", L"Shortcuts" },
+    // Include_launcher and AssociateFiles are handled separately and so do
+    // not need to be included in this list.
+    { nullptr, nullptr }
+};
+
+
+
 class PythonBootstrapperApplication : public CBalBaseBootstrapperApplication {
     void ShowPage(DWORD newPageId) {
         // Process each control for special handling in the new page.
         ProcessPageControls(ThemeGetPage(_theme, newPageId));
 
         // Enable disable controls per-page.
-        if (_pageIds[PAGE_INSTALL] == newPageId || _pageIds[PAGE_SIMPLE_INSTALL] == newPageId) {
+        if (_pageIds[PAGE_INSTALL] == newPageId ||
+            _pageIds[PAGE_SIMPLE_INSTALL] == newPageId ||
+            _pageIds[PAGE_UPGRADE] == newPageId) {
             InstallPage_Show();
         } else if (_pageIds[PAGE_CUSTOM1] == newPageId) {
             Custom1Page_Show();
@@ -222,7 +248,7 @@ class PythonBootstrapperApplication : public CBalBaseBootstrapperApplication {
         // On the install page set the focus to the install button or
         // the next enabled control if install is disabled
         if (_pageIds[PAGE_INSTALL] == newPageId) {
-            ThemeSetFocus(_theme, ID_INSTALL_ALL_USERS_BUTTON);
+            ThemeSetFocus(_theme, ID_INSTALL_BUTTON);
         } else if (_pageIds[PAGE_SIMPLE_INSTALL] == newPageId) {
             ThemeSetFocus(_theme, ID_INSTALL_SIMPLE_BUTTON);
         }
@@ -234,7 +260,7 @@ class PythonBootstrapperApplication : public CBalBaseBootstrapperApplication {
     void OnCommand(CONTROL_ID id) {
         LPWSTR defaultDir = nullptr;
         LPWSTR targetDir = nullptr;
-        LONGLONG elevated, crtInstalled;
+        LONGLONG elevated, crtInstalled, installAllUsers;
         BOOL checked;
         WCHAR wzPath[MAX_PATH] = { };
         BROWSEINFOW browseInfo = { };
@@ -247,87 +273,42 @@ class PythonBootstrapperApplication : public CBalBaseBootstrapperApplication {
             break;
 
         // Install commands
-        case ID_INSTALL_SIMPLE_BUTTON:
-            hr = BalGetStringVariable(L"TargetDir", &targetDir);
-            if (FAILED(hr) || !targetDir || !*targetDir) {
-                LONGLONG installAll;
-                if (SUCCEEDED(BalGetNumericVariable(L"InstallAllUsers", &installAll)) && installAll) {
-                    hr = BalGetStringVariable(L"DefaultAllUsersTargetDir", &defaultDir);
-                    BalExitOnFailure(hr, "Failed to get the default all users install directory");
-                } else {
-                    hr = BalGetStringVariable(L"DefaultJustForMeTargetDir", &defaultDir);
-                    BalExitOnFailure(hr, "Failed to get the default per-user install directory");
-                }
-
-                if (!defaultDir || !*defaultDir) {
-                    BalLogError(E_INVALIDARG, "Default install directory is blank");
-                }
-
-                hr = BalFormatString(defaultDir, &targetDir);
-                BalExitOnFailure1(hr, "Failed to format '%ls'", defaultDir);
-
-                hr = _engine->SetVariableString(L"TargetDir", targetDir);
-                ReleaseStr(targetDir);
-                BalExitOnFailure(hr, "Failed to set install target directory");
-            } else {
-                ReleaseStr(targetDir);
-            }
-
-            OnPlan(BOOTSTRAPPER_ACTION_INSTALL);
-            break;
-
-        case ID_INSTALL_ALL_USERS_BUTTON:
-            SavePageSettings();
-            
-            hr = _engine->SetVariableNumeric(L"InstallAllUsers", 1);
-            ExitOnFailure(hr, L"Failed to set install scope");
-
-            hr = _engine->SetVariableNumeric(L"CompileAll", 1);
-            ExitOnFailure(hr, L"Failed to set compile all setting");
-
-            hr = BalGetStringVariable(L"DefaultAllUsersTargetDir", &defaultDir);
-            BalExitOnFailure(hr, "Failed to get the default all users install directory");
-
-            if (!defaultDir || !*defaultDir) {
-                BalLogError(E_INVALIDARG, "Default install directory is blank");
-            }
-
-            hr = BalFormatString(defaultDir, &targetDir);
-            BalExitOnFailure1(hr, "Failed to format '%ls'", defaultDir);
-
-            hr = _engine->SetVariableString(L"TargetDir", targetDir);
-            ReleaseStr(targetDir);
-            BalExitOnFailure(hr, "Failed to set install target directory");
-
-            OnPlan(BOOTSTRAPPER_ACTION_INSTALL);
-            break;
-
-        case ID_INSTALL_JUST_FOR_ME_BUTTON:
+        case ID_INSTALL_SIMPLE_BUTTON: __fallthrough;
+        case ID_INSTALL_UPGRADE_BUTTON: __fallthrough;
+        case ID_INSTALL_BUTTON:
             SavePageSettings();
 
             if (!QueryElevateForCrtInstall()) {
                 break;
             }
 
-            hr = _engine->SetVariableNumeric(L"InstallAllUsers", 0);
-            ExitOnFailure(hr, L"Failed to set install scope");
+            hr = BalGetNumericVariable(L"InstallAllUsers", &installAllUsers);
+            ExitOnFailure(hr, L"Failed to get install scope");
 
-            hr = _engine->SetVariableNumeric(L"CompileAll", 0);
-            ExitOnFailure(hr, L"Failed to unset CompileAll");
+            hr = _engine->SetVariableNumeric(L"CompileAll", installAllUsers);
+            ExitOnFailure(hr, L"Failed to update CompileAll");
 
-            hr = BalGetStringVariable(L"DefaultJustForMeTargetDir", &defaultDir);
-            BalExitOnFailure(hr, "Failed to get the default per-user install directory");
+            hr = BalGetStringVariable(L"TargetDir", &targetDir);
+            if (FAILED(hr) || !targetDir || !targetDir[0]) {
+                ReleaseStr(targetDir);
 
-            if (!defaultDir || !*defaultDir) {
-                BalLogError(E_INVALIDARG, "Default install directory is blank");
-            }
+                hr = BalGetStringVariable(
+                    installAllUsers ? L"DefaultAllUsersTargetDir" : L"DefaultJustForMeTargetDir",
+                    &defaultDir
+                );
+                BalExitOnFailure(hr, "Failed to get the default install directory");
 
-            hr = BalFormatString(defaultDir, &targetDir);
-            BalExitOnFailure1(hr, "Failed to format '%ls'", defaultDir);
+                if (!defaultDir || !defaultDir[0]) {
+                    BalLogError(E_INVALIDARG, "Default install directory is blank");
+                }
 
-            hr = _engine->SetVariableString(L"TargetDir", targetDir);
+                hr = BalFormatString(defaultDir, &targetDir);
+                BalExitOnFailure1(hr, "Failed to format '%ls'", defaultDir);
+
+                hr = _engine->SetVariableString(L"TargetDir", targetDir);
+                BalExitOnFailure(hr, "Failed to set install target directory");
+            }
             ReleaseStr(targetDir);
-            BalExitOnFailure(hr, "Failed to set install target directory");
 
             OnPlan(BOOTSTRAPPER_ACTION_INSTALL);
             break;
@@ -342,6 +323,7 @@ class PythonBootstrapperApplication : public CBalBaseBootstrapperApplication {
             break;
 
         case ID_INSTALL_CUSTOM_BUTTON: __fallthrough;
+        case ID_INSTALL_UPGRADE_CUSTOM_BUTTON: __fallthrough;
         case ID_CUSTOM2_BACK_BUTTON:
             SavePageSettings();
             GoToPage(PAGE_CUSTOM1);
@@ -460,10 +442,11 @@ class PythonBootstrapperApplication : public CBalBaseBootstrapperApplication {
             elevated = 0;
         }
 
-        ThemeControlElevates(_theme, ID_INSTALL_ALL_USERS_BUTTON, !elevated);
 
-        if (SUCCEEDED(BalGetNumericVariable(L"InstallAllUsers", &installAll)) && installAll) {
-            ThemeControlElevates(_theme, ID_INSTALL_SIMPLE_BUTTON, !elevated);
+        if (SUCCEEDED(BalGetNumericVariable(L"InstallAllUsers", &installAll)) && installAll && !elevated) {
+            ThemeControlElevates(_theme, ID_INSTALL_BUTTON, TRUE);
+            ThemeControlElevates(_theme, ID_INSTALL_SIMPLE_BUTTON, TRUE);
+            ThemeControlElevates(_theme, ID_INSTALL_UPGRADE_BUTTON, TRUE);
         }
     }
 
@@ -667,7 +650,34 @@ public: // IBootstrapperApplication
 
         // Remember when our bundle would cause a downgrade.
         if (BOOTSTRAPPER_RELATED_OPERATION_DOWNGRADE == operation) {
-            _downgrading = TRUE;
+            _downgradingOtherVersion = TRUE;
+        } else if (BOOTSTRAPPER_RELATED_OPERATION_MAJOR_UPGRADE == operation) {
+            _upgradingOldVersion = TRUE;
+
+            // Assume we don't want the launcher or file associations, and if
+            // they have already been installed then loading the state will
+            // reactivate these settings.
+            _engine->SetVariableNumeric(L"Include_launcher", 0);
+            _engine->SetVariableNumeric(L"AssociateFiles", 0);
+            auto hr = LoadLauncherStateFromKey(_engine, HKEY_CURRENT_USER);
+            if (hr == S_FALSE) {
+                hr = LoadLauncherStateFromKey(_engine, HKEY_LOCAL_MACHINE);
+            }
+        } else if (BOOTSTRAPPER_RELATED_OPERATION_NONE == operation) {
+            if (_command.action == BOOTSTRAPPER_ACTION_INSTALL) {
+                LOC_STRING *pLocString = nullptr;
+                if (SUCCEEDED(LocGetString(_wixLoc, L"#(loc.FailureExistingInstall)", &pLocString)) && pLocString) {
+                    BalFormatString(pLocString->wzText, &_failedMessage);
+                } else {
+                    BalFormatString(L"Cannot install [WixBundleName] because it is already installed.", &_failedMessage);
+                }
+                BalLog(
+                    BOOTSTRAPPER_LOG_LEVEL_ERROR,
+                    "Related bundle %ls is preventing install",
+                    wzBundleId
+                );
+                SetState(PYBA_STATE_FAILED, E_WIXSTDBA_CONDITION_FAILED);
+            }
         }
 
         return CheckCanceled() ? IDCANCEL : IDOK;
@@ -1969,7 +1979,7 @@ private:
         BalExitOnFailure(hr, "Failed to update strings");
 
         // If we are going to apply a downgrade, bail.
-        if (_downgrading && BOOTSTRAPPER_ACTION_UNINSTALL < action) {
+        if (_downgradingOtherVersion && BOOTSTRAPPER_ACTION_UNINSTALL < action) {
             if (_suppressDowngradeFailure) {
                 BalLog(BOOTSTRAPPER_LOG_LEVEL_STANDARD, "A newer version of this product is installed but downgrade failure has been suppressed; continuing...");
             } else {
@@ -2354,7 +2364,9 @@ private:
                 if (_installPage == PAGE_LOADING) {
                     switch (_command.action) {
                     case BOOTSTRAPPER_ACTION_INSTALL:
-                        if (SUCCEEDED(BalGetNumericVariable(L"SimpleInstall", &simple)) && simple) {
+                        if (_upgradingOldVersion) {
+                            _installPage = PAGE_UPGRADE;
+                        } else if (SUCCEEDED(BalGetNumericVariable(L"SimpleInstall", &simple)) && simple) {
                             _installPage = PAGE_SIMPLE_INSTALL;
                         } else {
                             _installPage = PAGE_INSTALL;
@@ -2608,6 +2620,179 @@ private:
         }
     }
 
+    static bool IsTargetPlatformx64(__in IBootstrapperEngine* pEngine) {
+        WCHAR platform[8];
+        DWORD platformLen = 8;
+
+        if (FAILED(pEngine->GetVariableString(L"TargetPlatform", platform, &platformLen))) {
+            return S_FALSE;
+        }
+
+        return ::CompareStringW(LOCALE_NEUTRAL, 0, platform, -1, L"x64", -1) == CSTR_EQUAL;
+    }
+
+    static HRESULT LoadOptionalFeatureStatesFromKey(
+        __in IBootstrapperEngine* pEngine,
+        __in HKEY hkHive,
+        __in LPCWSTR subkey
+    ) {
+        HKEY hKey;
+        LRESULT res;
+
+        if (IsTargetPlatformx64(pEngine)) {
+            res = RegOpenKeyExW(hkHive, subkey, 0, KEY_READ | KEY_WOW64_64KEY, &hKey);
+        } else {
+            res = RegOpenKeyExW(hkHive, subkey, 0, KEY_READ | KEY_WOW64_32KEY, &hKey);
+        }
+        if (res == ERROR_FILE_NOT_FOUND) {
+            return S_FALSE;
+        }
+        if (res != ERROR_SUCCESS) {
+            return HRESULT_FROM_WIN32(res);
+        }
+
+        for (auto p = OPTIONAL_FEATURES; p->regName; ++p) {
+            res = RegQueryValueExW(hKey, p->regName, nullptr, nullptr, nullptr, nullptr);
+            if (res == ERROR_FILE_NOT_FOUND) {
+                pEngine->SetVariableNumeric(p->variableName, 0);
+            } else if (res == ERROR_SUCCESS) {
+                pEngine->SetVariableNumeric(p->variableName, 1);
+            } else {
+                RegCloseKey(hKey);
+                return HRESULT_FROM_WIN32(res);
+            }
+        }
+
+        RegCloseKey(hKey);
+        return S_OK;
+    }
+
+    static HRESULT LoadTargetDirFromKey(
+        __in IBootstrapperEngine* pEngine,
+        __in HKEY hkHive,
+        __in LPCWSTR subkey
+    ) {
+        HKEY hKey;
+        LRESULT res;
+        DWORD dataType;
+        BYTE buffer[1024];
+        DWORD bufferLen = sizeof(buffer);
+
+        if (IsTargetPlatformx64(pEngine)) {
+            res = RegOpenKeyExW(hkHive, subkey, 0, KEY_READ | KEY_WOW64_64KEY, &hKey);
+        } else {
+            res = RegOpenKeyExW(hkHive, subkey, 0, KEY_READ | KEY_WOW64_32KEY, &hKey);
+        }
+        if (res == ERROR_FILE_NOT_FOUND) {
+            return S_FALSE;
+        }
+        if (res != ERROR_SUCCESS) {
+            return HRESULT_FROM_WIN32(res);
+        }
+
+        res = RegQueryValueExW(hKey, nullptr, nullptr, &dataType, buffer, &bufferLen);
+        if (res == ERROR_SUCCESS && dataType == REG_SZ && bufferLen < sizeof(buffer)) {
+            pEngine->SetVariableString(L"TargetDir", reinterpret_cast<wchar_t*>(buffer));
+        }
+        RegCloseKey(hKey);
+        return HRESULT_FROM_WIN32(res);
+    }
+
+    static HRESULT LoadLauncherStateFromKey(
+        __in IBootstrapperEngine* pEngine,
+        __in HKEY hkHive
+    ) {
+        const LPCWSTR subkey = L"Software\\Python\\PyLauncher";
+        HKEY hKey;
+        LRESULT res;
+
+        if (IsTargetPlatformx64(pEngine)) {
+            res = RegOpenKeyExW(hkHive, subkey, 0, KEY_READ | KEY_WOW64_64KEY, &hKey);
+        } else {
+            res = RegOpenKeyExW(hkHive, subkey, 0, KEY_READ | KEY_WOW64_32KEY, &hKey);
+        }
+
+        if (res == ERROR_FILE_NOT_FOUND) {
+            return S_FALSE;
+        }
+        if (res != ERROR_SUCCESS) {
+            return HRESULT_FROM_WIN32(res);
+        }
+
+        res = RegQueryValueExW(hKey, nullptr, nullptr, nullptr, nullptr, nullptr);
+        if (res == ERROR_FILE_NOT_FOUND) {
+            pEngine->SetVariableNumeric(L"Include_launcher", 0);
+        } else if (res == ERROR_SUCCESS) {
+            pEngine->SetVariableNumeric(L"Include_launcher", 1);
+        }
+
+        res = RegQueryValueExW(hKey, L"AssociateFiles", nullptr, nullptr, nullptr, nullptr);
+        if (res == ERROR_FILE_NOT_FOUND) {
+            pEngine->SetVariableNumeric(L"AssociateFiles", 0);
+        } else if (res == ERROR_SUCCESS) {
+            pEngine->SetVariableNumeric(L"AssociateFiles", 1);
+        }
+
+        RegCloseKey(hKey);
+        return S_OK;
+    }
+
+    static void LoadOptionalFeatureStates(__in IBootstrapperEngine* pEngine) {
+        WCHAR subkeyFmt[256];
+        WCHAR subkey[256];
+        DWORD subkeyLen;
+        HRESULT hr;
+        HKEY hkHive;
+
+        // The launcher installation is separate from the Python install, so we
+        // check its state later. This also checks the file association option.
+
+        // Get the registry key from the bundle, to save having to duplicate it
+        // in multiple places.
+        subkeyLen = sizeof(subkeyFmt) / sizeof(subkeyFmt[0]);
+        hr = pEngine->GetVariableString(L"OptionalFeaturesRegistryKey", subkeyFmt, &subkeyLen);
+        BalExitOnFailure(hr, "Failed to locate registry key");
+        subkeyLen = sizeof(subkey) / sizeof(subkey[0]);
+        hr = pEngine->FormatString(subkeyFmt, subkey, &subkeyLen);
+        BalExitOnFailure1(hr, "Failed to format %ls", subkeyFmt);
+
+        // Check the current user's registry for existing features
+        hkHive = HKEY_CURRENT_USER;
+        hr = LoadOptionalFeatureStatesFromKey(pEngine, hkHive, subkey);
+        BalExitOnFailure1(hr, "Failed to read from HKCU\\%ls", subkey);
+        if (hr == S_FALSE) {
+            // Now check the local machine registry
+            hkHive = HKEY_LOCAL_MACHINE;
+            hr = LoadOptionalFeatureStatesFromKey(pEngine, hkHive, subkey);
+            BalExitOnFailure1(hr, "Failed to read from HKLM\\%ls", subkey);
+            if (hr == S_OK) {
+                // Found a system-wide install, so enable these settings.
+                pEngine->SetVariableNumeric(L"InstallAllUsers", 1);
+                pEngine->SetVariableNumeric(L"CompileAll", 1);
+            }
+        }
+
+        if (hr == S_OK) {
+            // Cannot change InstallAllUsersState when upgrading. While there's
+            // no good reason to not allow installing a per-user and an all-user
+            // version simultaneously, Burn can't handle the state management
+            // and will need to uninstall the old one. 
+            pEngine->SetVariableString(L"InstallAllUsersState", L"disable");
+
+            // Get the previous install directory. This can be changed by the
+            // user.
+            subkeyLen = sizeof(subkeyFmt) / sizeof(subkeyFmt[0]);
+            hr = pEngine->GetVariableString(L"TargetDirRegistryKey", subkeyFmt, &subkeyLen);
+            BalExitOnFailure(hr, "Failed to locate registry key");
+            subkeyLen = sizeof(subkey) / sizeof(subkey[0]);
+            hr = pEngine->FormatString(subkeyFmt, subkey, &subkeyLen);
+            BalExitOnFailure1(hr, "Failed to format %ls", subkeyFmt);
+            LoadTargetDirFromKey(pEngine, hkHive, subkey);
+        }
+
+    LExit:
+        return;
+    }
 
 public:
     //
@@ -2667,7 +2852,8 @@ public:
         _installPage = PAGE_LOADING;
         _hrFinal = hrHostInitialization;
 
-        _downgrading = FALSE;
+        _downgradingOtherVersion = FALSE;
+        _upgradingOldVersion = FALSE;
         _restartResult = BOOTSTRAPPER_APPLY_RESTART_NONE;
         _restartRequired = FALSE;
         _allowRestart = FALSE;
@@ -2690,6 +2876,8 @@ public:
 
         _hBAFModule = nullptr;
         _baFunction = nullptr;
+
+        LoadOptionalFeatureStates(pEngine);
     }
 
 
@@ -2748,7 +2936,8 @@ private:
     DWORD _calculatedCacheProgress;
     DWORD _calculatedExecuteProgress;
 
-    BOOL _downgrading;
+    BOOL _downgradingOtherVersion;
+    BOOL _upgradingOldVersion;
     BOOTSTRAPPER_APPLY_RESTART _restartResult;
     BOOL _restartRequired;
     BOOL _allowRestart;
diff --git a/Tools/msi/bundle/bootstrap/pythonba.vcxproj b/Tools/msi/bundle/bootstrap/pythonba.vcxproj
index 5d8337c134..be12957112 100644
--- a/Tools/msi/bundle/bootstrap/pythonba.vcxproj
+++ b/Tools/msi/bundle/bootstrap/pythonba.vcxproj
@@ -31,7 +31,7 @@
   <PropertyGroup Label="Configuration">
     <ConfigurationType>DynamicLibrary</ConfigurationType>
     <CharacterSet>Unicode</CharacterSet>
-    <IntDir>$(ProjectDir)..\..\obj\$(Configuration)_Bootstrap\</IntDir>
+    <IntDir>$(PySourcePath)PCBuild\obj\$(Configuration)_$(Platform)_Setup\Bootstrap\</IntDir>
     <OutDir>$(IntDir)</OutDir>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
diff --git a/Tools/msi/bundle/bundle.wxs b/Tools/msi/bundle/bundle.wxs
index 76e87ab623..678dac4e87 100644
--- a/Tools/msi/bundle/bundle.wxs
+++ b/Tools/msi/bundle/bundle.wxs
@@ -23,14 +23,18 @@
     <Variable Name="ShortVersion" Value="$(var.MajorVersionNumber).$(var.MinorVersionNumber)" />
     <Variable Name="ShortVersionNoDot" Value="$(var.MajorVersionNumber)$(var.MinorVersionNumber)" />
 
-    <Variable Name="InstallAllUsers" Value="0" Persisted="yes" bal:Overridable="yes" />
-    <Variable Name="TargetDir" Value="" Persisted="yes" bal:Overridable="yes" />
+    <Variable Name="InstallAllUsers" Value="0" bal:Overridable="yes" />
+    <Variable Name="TargetDir" Value="" bal:Overridable="yes" />
     <?if $(var.Platform)~="x64" ?>
     <Variable Name="DefaultAllUsersTargetDir" Value="[ProgramFiles64Folder]Python [ShortVersion]" bal:Overridable="yes" />
+    <Variable Name="TargetPlatform" Value="x64" />
     <?else ?>
     <Variable Name="DefaultAllUsersTargetDir" Value="[ProgramFilesFolder]Python [ShortVersion]" bal:Overridable="yes" />
+    <Variable Name="TargetPlatform" Value="x86" />
     <?endif ?>
     <Variable Name="DefaultJustForMeTargetDir" Value="[LocalAppDataFolder]Programs\Python\Python[ShortVersionNoDot]$(var.Suffix32)" bal:Overridable="yes" />
+    <Variable Name="OptionalFeaturesRegistryKey" Value="Software\$(var.TestPrefix)Python\PythonCore\[ShortVersion]$(var.Suffix32)\InstalledFeatures" />
+    <Variable Name="TargetDirRegistryKey" Value="Software\$(var.TestPrefix)Python\PythonCore\[ShortVersion]$(var.Suffix32)\InstallPath" />
     
     <!--
     An empty string will use the other defaults based on InstallAllUsers
@@ -44,23 +48,23 @@
     <Variable Name="TargetDirState" Value="enabled" />
     <Variable Name="CustomBrowseButtonState" Value="enabled" />
 
-    <Variable Name="Include_core" Value="1" Persisted="yes" />
-    <Variable Name="Include_exe" Value="1" Persisted="yes" bal:Overridable="yes" />
-    <Variable Name="Include_dev" Value="1" Persisted="yes" bal:Overridable="yes" />
-    <Variable Name="Include_lib" Value="1" Persisted="yes" bal:Overridable="yes" />
-    <Variable Name="Include_test" Value="1" Persisted="yes" bal:Overridable="yes" />
-    <Variable Name="Include_doc" Value="1" Persisted="yes" bal:Overridable="yes" />
-    <Variable Name="Include_tools" Value="1" Persisted="yes" bal:Overridable="yes" />
-    <Variable Name="Include_tcltk" Value="1" Persisted="yes" bal:Overridable="yes" />
-    <Variable Name="Include_pip" Value="1" Persisted="yes" bal:Overridable="yes" />
-    <Variable Name="Include_launcher" Value="1" Persisted="yes" bal:Overridable="yes" />
-    <Variable Name="Include_symbols" Value="0" Persisted="yes" bal:Overridable="yes" />
-    <Variable Name="Include_debug" Value="0" Persisted="yes" bal:Overridable="yes" />
+    <Variable Name="Include_core" Value="1" />
+    <Variable Name="Include_exe" Value="1" bal:Overridable="yes" />
+    <Variable Name="Include_dev" Value="1" bal:Overridable="yes" />
+    <Variable Name="Include_lib" Value="1" bal:Overridable="yes" />
+    <Variable Name="Include_test" Value="1" bal:Overridable="yes" />
+    <Variable Name="Include_doc" Value="1" bal:Overridable="yes" />
+    <Variable Name="Include_tools" Value="1" bal:Overridable="yes" />
+    <Variable Name="Include_tcltk" Value="1" bal:Overridable="yes" />
+    <Variable Name="Include_pip" Value="1" bal:Overridable="yes" />
+    <Variable Name="Include_launcher" Value="1" bal:Overridable="yes" />
+    <Variable Name="Include_symbols" Value="0" bal:Overridable="yes" />
+    <Variable Name="Include_debug" Value="0" bal:Overridable="yes" />
     
-    <Variable Name="AssociateFiles" Value="1" Persisted="yes" bal:Overridable="yes" />
-    <Variable Name="Shortcuts" Value="1" Persisted="yes" bal:Overridable="yes" />
-    <Variable Name="PrependPath" Value="0" Persisted="yes" bal:Overridable="yes" />
-    <Variable Name="CompileAll" Value="0" Persisted="yes" bal:Overridable="yes" />
+    <Variable Name="AssociateFiles" Value="1" bal:Overridable="yes" />
+    <Variable Name="Shortcuts" Value="1" bal:Overridable="yes" />
+    <Variable Name="PrependPath" Value="0" bal:Overridable="yes" />
+    <Variable Name="CompileAll" Value="0" bal:Overridable="yes" />
     
     <Variable Name="SimpleInstall" Value="0" bal:Overridable="yes" />
     
diff --git a/Tools/msi/bundle/packagegroups/core.wxs b/Tools/msi/bundle/packagegroups/core.wxs
index 9df6b79194..a789585837 100644
--- a/Tools/msi/bundle/packagegroups/core.wxs
+++ b/Tools/msi/bundle/packagegroups/core.wxs
@@ -9,6 +9,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and (Include_core or Include_exe or Include_launcher or Include_pip)">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="core_AllUsers_pdb"
                         SourceFile="core_pdb.msi"
@@ -17,6 +18,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and (Include_core or Include_exe or Include_launcher or Include_pip) and Include_symbols">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="core_AllUsers_d"
                         SourceFile="core_d.msi"
@@ -25,6 +27,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and (Include_core or Include_exe or Include_launcher or Include_pip) and Include_debug">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
 
             <MsiPackage Id="core_JustForMe"
@@ -34,6 +37,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and (Include_core or Include_exe or Include_launcher or Include_pip)">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="core_JustForMe_pdb"
                         SourceFile="core_pdb.msi"
@@ -42,6 +46,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and (Include_core or Include_exe or Include_launcher or Include_pip) and Include_symbols">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="core_JustForMe_d"
                         SourceFile="core_d.msi"
@@ -50,6 +55,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and (Include_core or Include_exe or Include_launcher or Include_pip) and Include_debug">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
         </PackageGroup>
     </Fragment>
diff --git a/Tools/msi/bundle/packagegroups/dev.wxs b/Tools/msi/bundle/packagegroups/dev.wxs
index f2ea29b611..f7f50250cb 100644
--- a/Tools/msi/bundle/packagegroups/dev.wxs
+++ b/Tools/msi/bundle/packagegroups/dev.wxs
@@ -9,6 +9,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and Include_dev">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="dev_AllUsers_d"
                         SourceFile="dev_d.msi"
@@ -17,6 +18,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and Include_dev and Include_debug">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
 
             <MsiPackage Id="dev_JustForMe"
@@ -26,6 +28,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and Include_dev">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="dev_JustForMe_d"
                         SourceFile="dev_d.msi"
@@ -34,6 +37,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and Include_dev and Include_debug">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
         </PackageGroup>
     </Fragment>
diff --git a/Tools/msi/bundle/packagegroups/doc.wxs b/Tools/msi/bundle/packagegroups/doc.wxs
index 7843f44263..2f11e27a92 100644
--- a/Tools/msi/bundle/packagegroups/doc.wxs
+++ b/Tools/msi/bundle/packagegroups/doc.wxs
@@ -10,6 +10,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and Include_doc">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             
             <MsiPackage Id="doc_JustForMe"
@@ -20,6 +21,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and Include_doc">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
         </PackageGroup>
     </Fragment>
diff --git a/Tools/msi/bundle/packagegroups/exe.wxs b/Tools/msi/bundle/packagegroups/exe.wxs
index 50346d94a1..03d6f62566 100644
--- a/Tools/msi/bundle/packagegroups/exe.wxs
+++ b/Tools/msi/bundle/packagegroups/exe.wxs
@@ -10,6 +10,7 @@
                         EnableFeatureSelection="yes"
                         InstallCondition="InstallAllUsers and (Include_exe or Include_launcher or Include_pip)">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="exe_AllUsers_pdb"
                         SourceFile="exe_pdb.msi"
@@ -18,6 +19,7 @@
                         DownloadUrl="$(var.DownloadUrl)"
                         InstallCondition="InstallAllUsers and (Include_exe or Include_launcher or Include_pip) and Include_symbols">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="exe_AllUsers_d"
                         SourceFile="exe_d.msi"
@@ -26,6 +28,7 @@
                         DownloadUrl="$(var.DownloadUrl)"
                         InstallCondition="InstallAllUsers and (Include_exe or Include_launcher or Include_pip) and Include_debug">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             
             <MsiPackage Id="exe_JustForMe"
@@ -36,6 +39,7 @@
                         EnableFeatureSelection="yes"
                         InstallCondition="not InstallAllUsers and (Include_exe or Include_launcher or Include_pip)">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="exe_JustForMe_pdb"
                         SourceFile="exe_pdb.msi"
@@ -44,6 +48,7 @@
                         DownloadUrl="$(var.DownloadUrl)"
                         InstallCondition="not InstallAllUsers and (Include_exe or Include_launcher or Include_pip) and Include_symbols">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="exe_JustForMe_d"
                         SourceFile="exe_d.msi"
@@ -52,6 +57,7 @@
                         DownloadUrl="$(var.DownloadUrl)"
                         InstallCondition="not InstallAllUsers and (Include_exe or Include_launcher or Include_pip) and Include_debug">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
         </PackageGroup>
     </Fragment>
diff --git a/Tools/msi/bundle/packagegroups/lib.wxs b/Tools/msi/bundle/packagegroups/lib.wxs
index 47a97f16d0..f7c57c8035 100644
--- a/Tools/msi/bundle/packagegroups/lib.wxs
+++ b/Tools/msi/bundle/packagegroups/lib.wxs
@@ -9,6 +9,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and Include_lib">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="lib_AllUsers_pdb"
                         SourceFile="lib_pdb.msi"
@@ -17,6 +18,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and Include_lib and Include_symbols">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="lib_AllUsers_d"
                         SourceFile="lib_d.msi"
@@ -25,6 +27,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and Include_lib and Include_debug">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
 
             <MsiPackage Id="lib_JustForMe"
@@ -34,6 +37,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and Include_lib">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="lib_JustForMe_pdb"
                         SourceFile="lib_pdb.msi"
@@ -42,6 +46,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and Include_lib and Include_symbols">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="lib_JustForMe_d"
                         SourceFile="lib_d.msi"
@@ -50,6 +55,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and Include_lib and Include_debug">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
         </PackageGroup>
     </Fragment>
diff --git a/Tools/msi/bundle/packagegroups/postinstall.wxs b/Tools/msi/bundle/packagegroups/postinstall.wxs
index 35978cc7c6..4c50001d2a 100644
--- a/Tools/msi/bundle/packagegroups/postinstall.wxs
+++ b/Tools/msi/bundle/packagegroups/postinstall.wxs
@@ -9,6 +9,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and Include_pip">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="pip_JustForMe"
                         SourceFile="pip.msi"
@@ -17,6 +18,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and Include_pip">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             
             <MsiPackage Id="path_AllUsers"
@@ -26,6 +28,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and PrependPath">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="path_JustForMe"
                         SourceFile="path.msi"
@@ -34,6 +37,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and PrependPath">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             
             <?define CompileAllCommand=-$(var.ShortVersion)$(var.Suffix32) -E -s -Wi "[TargetDir]\Lib\compileall.py" -f -x "bad_coding|badsyntax|site-packages|py2_|lib2to3\\tests|venv\\scripts" "[TargetDir]\Lib"?>
diff --git a/Tools/msi/bundle/packagegroups/tcltk.wxs b/Tools/msi/bundle/packagegroups/tcltk.wxs
index e0e3958d56..92f41cbc79 100644
--- a/Tools/msi/bundle/packagegroups/tcltk.wxs
+++ b/Tools/msi/bundle/packagegroups/tcltk.wxs
@@ -10,6 +10,7 @@
                         EnableFeatureSelection="yes"
                         InstallCondition="InstallAllUsers and Include_tcltk">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="tcltk_AllUsers_pdb"
                         SourceFile="tcltk_pdb.msi"
@@ -19,6 +20,7 @@
                         EnableFeatureSelection="yes"
                         InstallCondition="InstallAllUsers and Include_tcltk and Include_symbols">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="tcltk_AllUsers_d"
                         SourceFile="tcltk_d.msi"
@@ -28,6 +30,7 @@
                         EnableFeatureSelection="yes"
                         InstallCondition="InstallAllUsers and Include_tcltk and Include_debug">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
 
             <MsiPackage Id="tcltk_JustForMe"
@@ -38,6 +41,7 @@
                         EnableFeatureSelection="yes"
                         InstallCondition="not InstallAllUsers and Include_tcltk">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="tcltk_JustForMe_pdb"
                         SourceFile="tcltk_pdb.msi"
@@ -47,6 +51,7 @@
                         EnableFeatureSelection="yes"
                         InstallCondition="not InstallAllUsers and Include_tcltk and Include_symbols">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="tcltk_JustForMe_d"
                         SourceFile="tcltk_d.msi"
@@ -56,6 +61,7 @@
                         EnableFeatureSelection="yes"
                         InstallCondition="not InstallAllUsers and Include_tcltk and Include_debug">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
         </PackageGroup>
     </Fragment>
diff --git a/Tools/msi/bundle/packagegroups/test.wxs b/Tools/msi/bundle/packagegroups/test.wxs
index b64e8ff942..b3e0f3e922 100644
--- a/Tools/msi/bundle/packagegroups/test.wxs
+++ b/Tools/msi/bundle/packagegroups/test.wxs
@@ -9,6 +9,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and Include_test">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="test_AllUsers_pdb"
                         SourceFile="test_pdb.msi"
@@ -17,6 +18,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and Include_test and Include_symbols">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="test_AllUsers_d"
                         SourceFile="test_d.msi"
@@ -25,6 +27,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and Include_test and Include_debug">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
 
             <MsiPackage Id="test_JustForMe"
@@ -34,6 +37,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and Include_test">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="test_JustForMe_pdb"
                         SourceFile="test_pdb.msi"
@@ -42,6 +46,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and Include_test and Include_symbols">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             <MsiPackage Id="test_JustForMe_d"
                         SourceFile="test_d.msi"
@@ -50,6 +55,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and Include_test and Include_debug">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
         </PackageGroup>
     </Fragment>
diff --git a/Tools/msi/bundle/packagegroups/tools.wxs b/Tools/msi/bundle/packagegroups/tools.wxs
index 06af5b588f..c92f27ba01 100644
--- a/Tools/msi/bundle/packagegroups/tools.wxs
+++ b/Tools/msi/bundle/packagegroups/tools.wxs
@@ -9,6 +9,7 @@
                         ForcePerMachine="yes"
                         InstallCondition="InstallAllUsers and Include_tools">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
             
             <MsiPackage Id="tools_JustForMe"
@@ -18,6 +19,7 @@
                         ForcePerMachine="no"
                         InstallCondition="not InstallAllUsers and Include_tools">
                 <MsiProperty Name="TARGETDIR" Value="[TargetDir]" />
+                <MsiProperty Name="OPTIONALFEATURESREGISTRYKEY" Value="[OptionalFeaturesRegistryKey]" />
             </MsiPackage>
         </PackageGroup>
     </Fragment>
diff --git a/Tools/msi/common.wxs b/Tools/msi/common.wxs
index 7529aab0c6..cc39540a2b 100644
--- a/Tools/msi/common.wxs
+++ b/Tools/msi/common.wxs
@@ -5,6 +5,15 @@
     </Fragment>
     
     <Fragment>
+        <Component Id="OptionalFeature" Guid="*" Directory="InstallDirectory">
+            <Condition>OPTIONALFEATURESREGISTRYKEY</Condition>
+            <RegistryKey Root="HKMU" Key="[OPTIONALFEATURESREGISTRYKEY]">
+                <RegistryValue Type="string" Name="$(var.OptionalFeatureName)" Value="$(var.Version)" KeyPath="yes" />
+            </RegistryKey>
+        </Component>
+    </Fragment>
+    
+    <Fragment>
         <Property Id="UpgradeTable" Value="1" />
         
         <Upgrade Id="$(var.UpgradeCode)">
diff --git a/Tools/msi/core/core_d.wxs b/Tools/msi/core/core_d.wxs
index 8422117db9..bb35f994be 100644
--- a/Tools/msi/core/core_d.wxs
+++ b/Tools/msi/core/core_d.wxs
@@ -8,6 +8,7 @@
         
         <Feature Id="DebugBinaries" AllowAdvertise="no" Title="!(loc.Title_d)" Description="!(loc.Description_d)">
             <ComponentGroupRef Id="core_dll_d" />
+            <ComponentRef Id="OptionalFeature" />
         </Feature>
     </Product>
 </Wix>
diff --git a/Tools/msi/core/core_pdb.wxs b/Tools/msi/core/core_pdb.wxs
index c9a558d2c7..ba72d956cd 100644
--- a/Tools/msi/core/core_pdb.wxs
+++ b/Tools/msi/core/core_pdb.wxs
@@ -8,6 +8,7 @@
         
         <Feature Id="Symbols" AllowAdvertise="no" Title="!(loc.TitlePdb)" Description="!(loc.DescriptionPdb)">
             <ComponentGroupRef Id="core_symbols" />
+            <ComponentRef Id="OptionalFeature" />
         </Feature>
     </Product>
 </Wix>
diff --git a/Tools/msi/dev/dev.wxs b/Tools/msi/dev/dev.wxs
index f8af9aab5c..a09e139c42 100644
--- a/Tools/msi/dev/dev.wxs
+++ b/Tools/msi/dev/dev.wxs
@@ -13,6 +13,7 @@
 <?ifdef IncludeMinGWLib ?>
             <ComponentGroupRef Id="dev_mingw" />
 <?endif ?>
+            <ComponentRef Id="OptionalFeature" />
         </Feature>
     </Product>
 </Wix>
diff --git a/Tools/msi/doc/doc.wxs b/Tools/msi/doc/doc.wxs
index 22b0213932..bbe30a13e3 100644
--- a/Tools/msi/doc/doc.wxs
+++ b/Tools/msi/doc/doc.wxs
@@ -9,13 +9,16 @@
         
         <Feature Id="DefaultFeature" AllowAdvertise="no" Title="!(loc.Title)" Description="!(loc.Description)">
             <ComponentGroupRef Id="doc" Primary="yes" />
+            <ComponentRef Id="OptionalFeature" />
         </Feature>
         <Feature Id="Shortcuts" AllowAdvertise="no" Title="!(loc.Title)" Description="!(loc.Description)">
             <ComponentGroupRef Id="doc" />
             
             <?ifdef DocFilename ?>
             <Component Id="doc_shortcut" Directory="MenuDir" Guid="*">
-                <RegistryValue Root="HKMU" Key="[REGISTRYKEY]\DocShortcuts" Type="integer" Value="1" KeyPath="yes" />
+                <RegistryKey Root="HKMU" Key="[OPTIONALFEATURESREGISTRYKEY]">
+                    <RegistryValue Name="$(var.OptionalFeatureName)_shortcut" Type="string" Value="$(var.Version)" KeyPath="yes" />
+                </RegistryKey>
                 <Shortcut Id="python.chm"
                           Target="[#python.chm]"
                           Name="!(loc.ShortcutName)"
diff --git a/Tools/msi/exe/exe.wxs b/Tools/msi/exe/exe.wxs
index d8b05e0f58..dcbf646da0 100644
--- a/Tools/msi/exe/exe.wxs
+++ b/Tools/msi/exe/exe.wxs
@@ -11,6 +11,7 @@
             <ComponentGroupRef Id="exe_python" Primary="yes" />
             <ComponentGroupRef Id="exe_txt" />
             <ComponentGroupRef Id="exe_icons" />
+            <ComponentRef Id="OptionalFeature" />
         </Feature>
             
         <Feature Id="Shortcuts" AllowAdvertise="no" Title="!(loc.Title)" Description="!(loc.Description)">
@@ -23,6 +24,7 @@
                 <RemoveFolder Id="Remove_MenuDir" Directory="MenuDir" On="uninstall" />
                 <RegistryKey Root="HKMU" Key="[REGISTRYKEY]">
                     <RegistryValue Key="InstallPath\InstallGroup" Type="string" Value="!(loc.ProductName)" KeyPath="yes" />
+                    <RegistryValue Key="InstalledFeatures" Name="Shortcuts" Type="string" Value="$(var.Version)" />
                 </RegistryKey>
             </Component>
         </Feature>
diff --git a/Tools/msi/exe/exe_files.wxs b/Tools/msi/exe/exe_files.wxs
index 642237299f..3b5fce446c 100644
--- a/Tools/msi/exe/exe_files.wxs
+++ b/Tools/msi/exe/exe_files.wxs
@@ -23,6 +23,7 @@
                 
                 <RegistryKey Root="HKMU" Key="[REGISTRYKEY]">
                     <RegistryValue Key="InstallPath" Type="string" Value="[InstallDirectory]" KeyPath="no" />
+                    <RegistryValue Key="InstallPath" Name="ExecutablePath" Type="string" Value="[#python.exe]" KeyPath="no" />
                 </RegistryKey>
             </Component>
             <Component Id="pythonw.exe" Directory="InstallDirectory" Guid="$(var.PythonwExeComponentGuid)">
diff --git a/Tools/msi/launcher/launcher_files.wxs b/Tools/msi/launcher/launcher_files.wxs
index 9606dc6dd2..589dee5654 100644
--- a/Tools/msi/launcher/launcher_files.wxs
+++ b/Tools/msi/launcher/launcher_files.wxs
@@ -4,6 +4,7 @@
         <ComponentGroup Id="launcher_exe">
             <Component Id="py.exe" Directory="LauncherInstallDirectory" Guid="{B5107402-6958-461B-8B0A-4037D3327160}">
                 <File Id="py.exe" Name="py.exe" Source="py.exe" KeyPath="yes" />
+                <RegistryValue Root="HKMU" Key="Software\Python\PyLauncher" Value="[#py.exe]" Type="string" />
             </Component>
             <Component Id="pyw.exe" Directory="LauncherInstallDirectory" Guid="{8E52B8CD-48BB-4D74-84CD-6238BCD11F20}">
                 <File Id="pyw.exe" Name="pyw.exe" Source="pyw.exe" KeyPath="yes" />
@@ -12,12 +13,12 @@
             <Component Id="launcher_path_cu" Directory="LauncherInstallDirectory" Guid="{95AEB930-367C-475C-A17E-A89BFCD4C670}">
                 <Condition>NOT ALLUSERS=1</Condition>
                 
-                <RegistryValue KeyPath="yes" Root="HKMU" Key="Software\Python\PyLauncher\InstallDir" Value="[LauncherInstallDirectory]" Type="string" />
+                <RegistryValue KeyPath="yes" Root="HKMU" Key="Software\Python\PyLauncher" Name="InstallDir" Value="[LauncherInstallDirectory]" Type="string" />
                 <Environment Id="PATH_CU" Action="set" Name="PATH" Part="first" Value="[LauncherInstallDirectory]" />
             </Component>
             <Component Id="launcher_path_lm" Directory="LauncherInstallDirectory" Guid="{4A41C365-4E27-4D38-A6D1-4A01B4A6500C}">
                 <Condition>ALLUSERS=1</Condition>
-                <RegistryValue KeyPath="yes" Root="HKMU" Key="Software\Python\PyLauncher\InstallDir" Value="[LauncherInstallDirectory]" Type="string" />
+                <RegistryValue KeyPath="yes" Root="HKMU" Key="Software\Python\PyLauncher" Name="InstallDir" Value="[LauncherInstallDirectory]" Type="string" />
             </Component>
         </ComponentGroup>
     </Fragment>
diff --git a/Tools/msi/launcher/launcher_reg.wxs b/Tools/msi/launcher/launcher_reg.wxs
index 204b4ed261..eef71c8d39 100644
--- a/Tools/msi/launcher/launcher_reg.wxs
+++ b/Tools/msi/launcher/launcher_reg.wxs
@@ -3,7 +3,7 @@
     <Fragment>
         <ComponentGroup Id="launcher_reg">
             <Component Id="file_association" Directory="LauncherInstallDirectory" Guid="{5AF84D9A-D820-456B-B230-6E0105A50276}">
-                <RegistryValue KeyPath="yes" Root="HKMU" Key="Software\Python\PyLauncher\AssociateFiles" Value="1" Type="integer" />
+                <RegistryValue KeyPath="yes" Root="HKMU" Key="Software\Python\PyLauncher" Name="AssociateFiles" Value="1" Type="integer" />
                 
                 <ProgId Id="$(var.TestPrefix)Python.File" Description="!(loc.PythonFileDescription)" Advertise="no" Icon="py.exe" IconIndex="1">
                     <Extension Id="$(var.FileExtension)" ContentType="text/plain">
diff --git a/Tools/msi/lib/lib.wxs b/Tools/msi/lib/lib.wxs
index b1aec75a7c..2b04bcb304 100644
--- a/Tools/msi/lib/lib.wxs
+++ b/Tools/msi/lib/lib.wxs
@@ -11,6 +11,7 @@
             <ComponentGroupRef Id="lib_py" />
             <ComponentGroupRef Id="lib_files" />
             <ComponentGroupRef Id="lib_extensions" />
+            <ComponentRef Id="OptionalFeature" />
         </Feature>
     </Product>
 </Wix>
diff --git a/Tools/msi/msi.props b/Tools/msi/msi.props
index bd22345ec3..1d9f0f0df1 100644
--- a/Tools/msi/msi.props
+++ b/Tools/msi/msi.props
@@ -43,7 +43,7 @@
     </ItemGroup>
 
     <PropertyGroup>
-        <IntermediateOutputPath>$(MSBuildThisFileDirectory)\obj\$(Configuration)_$(Platform)\$(OutputName)</IntermediateOutputPath>
+        <IntermediateOutputPath>$(PySourcePath)PCBuild\obj\$(Configuration)_$(Platform)_Setup\$(OutputName)</IntermediateOutputPath>
         <IntermediateOutputPath Condition="'$(OutputSuffix)' != ''">$(IntermediateOutputPath)_$(OutputSuffix)</IntermediateOutputPath>
         <OutputPath Condition="'$(OutputPath)' == ''">$(BuildPath)</OutputPath>
         <OutputPath Condition="!HasTrailingSlash($(OutputPath))">$(OutputPath)\</OutputPath>
@@ -71,6 +71,7 @@
             NextMajorVersionNumber=$(MajorVersionNumber).$([msbuild]::Add($(MinorVersionNumber), 1)).0.0;
             Bitness=$(Bitness);
             PyDebugExt=$(PyDebugExt);
+            OptionalFeatureName=$(OutputName);
         </DefineConstants>
         <DefineConstants Condition="'$(CRTRedist)' != ''">
             $(DefineConstants);CRTRedist=$(CRTRedist);
@@ -112,9 +113,6 @@
         <LinkerBindInputPaths Include="$(CRTRedist)" Condition="'$(CRTRedist)' != ''">
             <BindName>redist</BindName>
         </LinkerBindInputPaths>
-        <LinkerBindInputPaths Include="$(CRTRedist)\$(Platform)" Condition="'$(CRTRedist)' != ''">
-            <BindName>crt</BindName>
-        </LinkerBindInputPaths>
     </ItemGroup>
 
     <Target Name="_ValidateMsiProps" BeforeTargets="PrepareForBuild">
diff --git a/Tools/msi/path/path.wxs b/Tools/msi/path/path.wxs
index 7e462e26e9..8b37936cc9 100644
--- a/Tools/msi/path/path.wxs
+++ b/Tools/msi/path/path.wxs
@@ -9,7 +9,9 @@
         <Feature Id="DefaultFeature" AllowAdvertise="no" Title="!(loc.Title)" Description="!(loc.Description)">
             <Component Id="PrependPath_CU" Directory="InstallDirectory" Guid="*">
                 <Condition>NOT ALLUSERS=1</Condition>
-                <RegistryValue KeyPath="yes" Root="HKCU" Key="[REGISTRYKEY]\PrependPath" Value="1" Type="integer" />
+                <RegistryKey Root="HKCU" Key="[REGISTRYKEY]">
+                    <RegistryValue KeyPath="yes" Key="InstalledFeatures" Name="$(var.OptionalFeatureName)" Value="$(var.Version)" Type="string" />
+                </RegistryKey>
                 
                 <CreateFolder Directory="Scripts" />
                 <RemoveFolder Id="Remove_Scripts_CU" Directory="Scripts" On="uninstall" />
@@ -19,7 +21,9 @@
             </Component>
             <Component Id="PrependPath_LM" Directory="InstallDirectory" Guid="*">
                 <Condition>ALLUSERS=1</Condition>
-                <RegistryValue KeyPath="yes" Root="HKLM" Key="[REGISTRYKEY]\PrependPath" Value="1" Type="integer" />
+                <RegistryKey Root="HKLM" Key="[REGISTRYKEY]">
+                    <RegistryValue KeyPath="yes" Key="InstalledFeatures" Name="$(var.OptionalFeatureName)" Value="$(var.Version)" Type="string" />
+                </RegistryKey>
                 
                 <CreateFolder Directory="Scripts" />
                 <RemoveFolder Id="Remove_Scripts_LM" Directory="Scripts" On="uninstall" />
diff --git a/Tools/msi/pip/pip.wxs b/Tools/msi/pip/pip.wxs
index c46a868188..19e9f5fd20 100644
--- a/Tools/msi/pip/pip.wxs
+++ b/Tools/msi/pip/pip.wxs
@@ -15,9 +15,7 @@
         <Condition Message="!(loc.NoPython)">PYTHON_EXE</Condition>
         
         <Feature Id="DefaultFeature" AllowAdvertise="no" Title="!(loc.Title)" Description="!(loc.Description)">
-            <Component Id="pip" Guid="*" Directory="InstallDirectory">
-                <RegistryValue KeyPath="yes" Root="HKMU" Key="[REGISTRYKEY]\EnsurePipRun" Value="1" Type="integer" />
-            </Component>
+            <ComponentRef Id="OptionalFeature" />
         </Feature>
         
         <?if $(var.Platform)~="x64" ?>
diff --git a/Tools/msi/tcltk/tcltk.wxs b/Tools/msi/tcltk/tcltk.wxs
index 5def5ed4db..0b83c5cb5c 100644
--- a/Tools/msi/tcltk/tcltk.wxs
+++ b/Tools/msi/tcltk/tcltk.wxs
@@ -30,6 +30,7 @@
             <Component Id="idle_reg" Directory="InstallDirectory">
                 <RegistryValue KeyPath="yes" Root="HKMU" Key="[REGISTRYKEY]\Idle" Type="string" Value="[#Lib_idlelib_idle.pyw]" />
             </Component>
+            <ComponentRef Id="OptionalFeature" />
         </Feature>
         <Feature Id="AssociateFiles" AllowAdvertise="no" Title="!(loc.Title)" Description="!(loc.Description)">
             <ComponentGroupRef Id="tkinter_lib" />
diff --git a/Tools/msi/test/test.wxs b/Tools/msi/test/test.wxs
index de477858eb..f2ed64f07b 100644
--- a/Tools/msi/test/test.wxs
+++ b/Tools/msi/test/test.wxs
@@ -10,6 +10,7 @@
         <Feature Id="DefaultFeature" AllowAdvertise="no" Title="!(loc.Title)" Description="!(loc.Description)">
             <ComponentGroupRef Id="test_py" />
             <ComponentGroupRef Id="test_extensions" />
+            <ComponentRef Id="OptionalFeature" />
         </Feature>
     </Product>
 </Wix>
diff --git a/Tools/msi/tools/tools.wxs b/Tools/msi/tools/tools.wxs
index 366d4c68f3..8f8418a46c 100644
--- a/Tools/msi/tools/tools.wxs
+++ b/Tools/msi/tools/tools.wxs
@@ -9,6 +9,7 @@
         <Feature Id="DefaultFeature" AllowAdvertise="no" Title="!(loc.Title)" Description="!(loc.Description)">
             <ComponentGroupRef Id="tools_py" />
             <ComponentGroupRef Id="tools_scripts" />
+            <ComponentRef Id="OptionalFeature" />
         </Feature>
     </Product>
 </Wix>