diff --git a/viogpu/viogpu3d/tools/prepare_package_inx.ps1 b/viogpu/viogpu3d/tools/prepare_package_inx.ps1
index 3aa0b4d3..92cf27b6 100644
--- a/viogpu/viogpu3d/tools/prepare_package_inx.ps1
+++ b/viogpu/viogpu3d/tools/prepare_package_inx.ps1
@@ -17,9 +17,10 @@ if (-not (Test-Path -LiteralPath $SourcePath)) {
 }
 
 $sourceName = [System.IO.Path]::GetFileName($SourcePath)
-if ($sourceName -like 'viogpu3d_x64*') {
-  if ([string]::IsNullOrWhiteSpace($Yttrium12Path) -or
-      -not (Test-Path -LiteralPath $Yttrium12Path -PathType Leaf)) {
+$yttrium12Present = $sourceName -like 'viogpu3d_x64*' -and
+  -not [string]::IsNullOrWhiteSpace($Yttrium12Path)
+if ($yttrium12Present) {
+  if (-not (Test-Path -LiteralPath $Yttrium12Path -PathType Leaf)) {
     throw "Missing x64 Yttrium12 payload: $Yttrium12Path. Build yttrium12 first and set YTTRIUM12_DLL_x64."
   }
 
@@ -62,6 +63,13 @@ if ($hasWow64Payload -and -not $wow64LvpPresent) {
 }
 
 $lines = [System.IO.File]::ReadAllLines($SourcePath)
+if (-not $yttrium12Present) {
+  # Drop the optional DX12 slot without removing the DX9/DX10/DX11 entries
+  # on the same registry lines. The remaining matches are file entries.
+  $lines = $lines -replace ',%11%\\yttrium12\.dll\s*$', ''
+  $lines = $lines -replace ',yttrium12\s*$', ''
+  $removeTokens += @('yttrium12_x64.dll')
+}
 if ($removeTokens.Count -ne 0) {
   $pattern = ($removeTokens | ForEach-Object { [regex]::Escape($_) }) -join '|'
   $lines = @($lines | Where-Object { $_ -notmatch $pattern })
@@ -75,4 +83,4 @@ if (-not (Test-Path -LiteralPath $destinationDir)) {
 $utf8NoBom = New-Object System.Text.UTF8Encoding($false)
 [System.IO.File]::WriteAllLines($DestinationPath, $lines, $utf8NoBom)
 
-Write-Host "Prepared $DestinationPath (native Lavapipe=$nativeLvpPresent, wow64 Lavapipe=$wow64LvpPresent, Yttrium12=$Yttrium12Path)"
+Write-Host "Prepared $DestinationPath (native Lavapipe=$nativeLvpPresent, wow64 Lavapipe=$wow64LvpPresent, Yttrium12=$yttrium12Present)"
diff --git a/viogpu/viogpu3d/viogpu3d.vcxproj b/viogpu/viogpu3d/viogpu3d.vcxproj
index 596c8d82..764fe64d 100644
--- a/viogpu/viogpu3d/viogpu3d.vcxproj
+++ b/viogpu/viogpu3d/viogpu3d.vcxproj
@@ -462,12 +462,14 @@
   </ItemGroup>
   <PropertyGroup>
     <MesaStageDir>$(IntDir)messa_stage\</MesaStageDir>
-    <YTTRIUM12_DLL_x64 Condition="'$(YTTRIUM12_DLL_x64)' == ''">$(MSBuildProjectDirectory)\..\..\..\yttrium12\yttrium12.dll</YTTRIUM12_DLL_x64>
   </PropertyGroup>
   <Target Name="StageYttrium12Dll" BeforeTargets="PrepareForBuild" DependsOnTargets="UpdateInxFile" Condition="'$(Platform)' == 'x64' AND Exists('$(MESA_PREFIX_x64)\bin\viogpu_d3d10.dll')">
-    <Error Condition="!Exists('$(YTTRIUM12_DLL_x64)')" Text="Missing x64 Yttrium12 payload: $(YTTRIUM12_DLL_x64). Build yttrium12 first and set YTTRIUM12_DLL_x64." />
-    <MakeDir Directories="$(MesaStageDir)x64" />
-    <Copy SourceFiles="$(YTTRIUM12_DLL_x64)" DestinationFiles="$(MesaStageDir)x64\yttrium12_x64.dll" />
+    <Error Condition="'$(YTTRIUM12_DLL_x64)' != '' AND !Exists('$(YTTRIUM12_DLL_x64)')" Text="Missing x64 Yttrium12 payload: $(YTTRIUM12_DLL_x64). Build yttrium12 first and set YTTRIUM12_DLL_x64." />
+    <MakeDir Condition="'$(YTTRIUM12_DLL_x64)' != ''" Directories="$(MesaStageDir)x64" />
+    <Copy Condition="'$(YTTRIUM12_DLL_x64)' != ''" SourceFiles="$(YTTRIUM12_DLL_x64)" DestinationFiles="$(MesaStageDir)x64\yttrium12_x64.dll" />
+    <Delete Condition="'$(YTTRIUM12_DLL_x64)' == ''" Files="$(MesaStageDir)x64\yttrium12_x64.dll" />
+    <!-- WDK packaging copies incrementally, so remove a previous opt-in payload. -->
+    <Delete Condition="'$(YTTRIUM12_DLL_x64)' == '' AND '$(PackageDir)' != ''" Files="$(PackageDir)x64\yttrium12_x64.dll" />
   </Target>
   <Target Name="StageMesaDlls" BeforeTargets="PrepareForBuild">
     <MakeDir Condition="Exists('$(MESA_PREFIX_x64)\bin\viogpu_d3d10.dll')" Directories="$(MesaStageDir)x64" />
@@ -513,7 +515,7 @@
     <FilesToPackage Include="$(MesaStageDir)x64\viogpu_d3d10_x64.dll">
       <PackageRelativeDirectory>x64</PackageRelativeDirectory>
     </FilesToPackage>
-    <FilesToPackage Include="$(MesaStageDir)x64\yttrium12_x64.dll">
+    <FilesToPackage Condition="'$(YTTRIUM12_DLL_x64)' != ''" Include="$(MesaStageDir)x64\yttrium12_x64.dll">
       <PackageRelativeDirectory>x64</PackageRelativeDirectory>
     </FilesToPackage>
     <FilesToPackage Include="$(MesaStageDir)x64\viogpu_wgl_x64.dll">
@@ -619,7 +621,7 @@
   </ItemGroup>
   <ItemGroup Condition="'$(Platform)' == 'x64' AND Exists('$(MESA_PREFIX_x64)\bin\viogpu_d3d10.dll')">
     <PackOne_Files Include="$(MesaStageDir)x64\viogpu_d3d10_x64.dll"><PackOne_Subdir>x64</PackOne_Subdir></PackOne_Files>
-    <PackOne_Files Include="$(MesaStageDir)x64\yttrium12_x64.dll"><PackOne_Subdir>x64</PackOne_Subdir></PackOne_Files>
+    <PackOne_Files Condition="'$(YTTRIUM12_DLL_x64)' != ''" Include="$(MesaStageDir)x64\yttrium12_x64.dll"><PackOne_Subdir>x64</PackOne_Subdir></PackOne_Files>
     <PackOne_Files Include="$(MesaStageDir)x64\viogpu_wgl_x64.dll"><PackOne_Subdir>x64</PackOne_Subdir></PackOne_Files>
     <PackOne_Files Include="$(MesaStageDir)x64\libEGL_x64.dll"><PackOne_Subdir>x64</PackOne_Subdir></PackOne_Files>
     <PackOne_Files Include="$(MesaStageDir)x64\libGLESv1_CM_x64.dll"><PackOne_Subdir>x64</PackOne_Subdir></PackOne_Files>