diff --git a/PropertySheets/Platform.props b/PropertySheets/Platform.props
index 8e043f9db..7a6c21b07 100644
--- a/PropertySheets/Platform.props
+++ b/PropertySheets/Platform.props
@@ -2,7 +2,7 @@
 <Project DefaultTargets="Build" ToolsVersion="12.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
 
   <PropertyGroup Label="Configuration">
-    <PlatformToolset>$(DefaultPlatformToolset)_xp</PlatformToolset>
+    <PlatformToolset Condition="'$(DefaultPlatformToolset)'!=''">$(DefaultPlatformToolset)_xp</PlatformToolset>
   </PropertyGroup>
 
   <ImportGroup Label="PropertySheets">