Why does opening the solution always results in check out of unit test project file?

I use VS2010开发者_运维百科 with solutions in .net 4.0. Most of the solutions have unit test projects in them. The solutions are under source control (TFS 2010).

But every time I open a solution, VS2010 checked out the test project file (.csproj) and the corresponding .csproj.vspscc file. When i compare the checked out files with the ones under source control (TFS), the files are the same.

Does anyone know a solution to this problem?

I found out what the problem was with my VS2010. I installed the 'Solution Load Manager' extension (version 0.2.1).

After disabling this extension, the projects where not checked out anymore during a get latest version.