Thanks for the replies, though I did know which CLR's worked on what versions. Smiley

Is this a known issue by the way or just me?

When I try to run some of the tools:

C:\Program Files\Microsoft Visual Studio 9.0\SDK\v3.5\Bin>sgen

Unhandled Exception: System.IO.FileLoadException: Could not load file or assembly 'sgen, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. Strong name validation failed. (Exception from HRESULT:0x8013141A)
File name: 'sgen, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' ---> System.Security.SecurityException: Strong name validation failed. (Exception from HRESULT: 0x8013141A)
The Zone of the assembly that failed was:
MyComputer