API restriction: The assembly <WindowsBase.DLL> has already loaded from a different location.

I have been getting an error similar to the ones found here and here.

The difference is mine was for the WindowsBase.dll.  I tried removing the reference, restarting VS.NET, redoing the reference, restarting my machine, nothing wanted to work.  I was getting totally p!$$#d off!

So I created a new WPF app, attached all the files from my old app and …..   It worked.   Hope this helps someone else.