The located assembly's manifest definition does not match the assembly reference

Question

I am trying to run some unit tests in a C# Windows Forms application (Visual Studio 2005), and I get the following error:

System.IO.FileLoadException: Co

Answer 1

I just found another reason why to get this error. I cleaned my GAC from all versions of a specific library and built my project with reference to specific version deployed together with the executable. When I run the project I got this exception searching for a newer version of the library.

The reason was publisher policy. When I uninstalled library's versions from GAC I forgot to uninstall publisher policy assemblies as well so instead of using my locally deployed assembly the assembly loader found publisher policy in GAC which told it to search for a newer version.