diff --git a/PCbuild/x64.props b/PCbuild/x64.props
index 5f26e682960..4fb319bbbf8 100644
--- a/PCbuild/x64.props
+++ b/PCbuild/x64.props
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <PropertyGroup Label="UserMacros">
+  <PropertyGroup Label="UserMacros" Condition="'$(HOST_PYTHON)'!=''">
     <PythonExe>$(HOST_PYTHON)</PythonExe>
   </PropertyGroup>
   <PropertyGroup>
@@ -23,4 +23,4 @@
       <Value>$(PythonExe)</Value>
     </BuildMacro>
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>