The problem is as described in the title. This was in my case due to corrupted Visual Studio version control cached data.
I fixed it like this:
Run this in Visual Studio Comman Prompt:
Then navigate to your TFS data on HD, it should be around here:
There delete without mercy under the cache subfolder everything. Just be sure to backup the folder data before you do this, just in case.
After a organization I know updated successfully their TFS 2010 to TFS 2012 all was OK except that when you tired to access a project from TFS nothing would appear and no apparent error. After looking at the Visual Studio output window I noticed that a file caused problem. For some reason the following VersionControl.config file was empty and Visual Studio could not write to this file. Well I chose a direct approach and deleted the file and rebooted Visual Studio. Surprise surprise all is OK :). So if you encounter similar problem go to the following directory and delete your VersionControl.config file(notice mine was empty which indicated that something was wrong with the file): C:\Users\”your windows user name”\AppData\Local\Microsoft\Team Foundation\3.0\Cache