# Check for .NET 4.5.2 in WiX

I'm trying to make use of the WIX_IS_NETFRAMEWORK_452_OR_LATER_INSTALLED property. I've read the How-To. Specifically, I have:

• Added a reference to WixNetFxExtension.dll (located at C:\Program Files (x86)\WiX Toolset v3.9\bin\\WixNetFxExtension.dll)
• Added xmlns:netfx="http://schemas.microsoft.com/wix/NetFxExtension" to my <Wix> tag.
• Referenced my property: <PropertyRef Id="WIX_IS_NETFRAMEWORK_452_OR_LATER_INSTALLED"/>

But I get the following error when I try to compile:

Error 8 Unresolved reference to symbol 'Property:WIX_IS_NETFRAMEWORK_452_OR_LATER_INSTALLED' in section 'Product:*'. C:\Code\Installer\Product.wxs 46 1 WiXInstaller

Any ideas on how to solve this problem?

Edit: I don't see any references to WIX_IS_NETFRAMEWORK_452_OR_LATER_INSTALLED in the 3.9 source code, so why is it in the documentation?

Those properties are new to WiX v3.10.