The cache file C:\Users\Admin\AppData\Local\Microsoft\Team Foundation\4.0\Cache\VersionControl.config is not valid and cannot be loaded.

If you are working with TFS and get the above error, the possibility is the VersionControl.config file is corrupted and because of which you are not able to connect to TFS Server from Visual Studio.

 To get rid of the problem I had to just delete the VersionControl.config file and tried connecting to TFS from Visual Studio, it creates a new config file and everything works fine.