diff --git a/tooling/Microsoft.VisualStudio.RazorExtension/Microsoft.VisualStudio.RazorExtension.csproj b/tooling/Microsoft.VisualStudio.RazorExtension/Microsoft.VisualStudio.RazorExtension.csproj
index d0ea92c25b..1dc1d55981 100644
--- a/tooling/Microsoft.VisualStudio.RazorExtension/Microsoft.VisualStudio.RazorExtension.csproj
+++ b/tooling/Microsoft.VisualStudio.RazorExtension/Microsoft.VisualStudio.RazorExtension.csproj
@@ -2,8 +2,12 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="15.0">
   <PropertyGroup>
     <VsixVersion>15.8</VsixVersion>
-    <VsixVersion Condition="'$(BuildNumber)'!=''">$(VsixVersion).$(BuildNumber)</VsixVersion>
-    <VsixVersion Condition="'$(BuildNumber)'==''">$(VsixVersion).999999</VsixVersion>
+    
+    <!-- VS does not like letters in package versions -->
+    <VSIXBuildNumber Condition="'$(BuildNumber)' == 't000'">99999</VSIXBuildNumber>
+    <VSIXBuildNumber Condition="'$(VSIXBuildNumber)' == ''">$(BuildNumber)</VSIXBuildNumber>
+    <VsixVersion Condition="'$(VSIXBuildNumber)'!=''">$(VsixVersion).$(VSIXBuildNumber)</VsixVersion>
+    <VsixVersion Condition="'$(VSIXBuildNumber)'==''">$(VsixVersion).999999</VsixVersion>
     <MinimumVisualStudioVersion>15.0</MinimumVisualStudioVersion>
     <VSToolsPath Condition="'$(VSToolsPath)' == ''">$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)</VSToolsPath>
     <NuGetPackageImportStamp>