I just had an interesting problem with one of our offshore developers. She couldn’t connect to our TFS server and was getting the dreaded “TF31002: Unable to connect” error. It turned out that we could connect using a different account on the same box she was using and that she was able to connect herself from other boxes. That ruled out the common firewall blocking issue.
In the end, we logged into the problem box with a different account and renamed her profile on disk (not deleted so she could retrieve anything she needed). We then ran devenv (“run-as”) with her account which created a fresh profile. The connection to TFS then worked and we could see the VersionConfig and ServerMap files had been created successfully in her new profile. A quick sanity check by logging into the box as her again and running Visual Studio showed the problem to be fixed. What was broken in her local profile on the box I do not know.