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 got this error while building on Team Foundation Server's build-service. It turned out I had multiple projects in my solution using different versions of the same library added with NuGet. I removed all old versions with NuGet and added the new one as reference for all.

Team Foundation Server puts all DLL files in one directory, and there can only be one DLL file of a certain name at a time of course.