I recently had to migrate multiple source repositories from TFS to GIT (Git on vsonline). To do so I used Git Tfs https://github.com/git-tfs/git-tfs which does the job and is well documented https://github.com/git-tfs/git-tfs/blob/master/doc/usecases/migrate_tfs_to_git.md
There’s one step where they instruct you to remove *.vspscc and *.vssscc files and to clean up *.sln and *.*proj files from TFS references.
This will prevent Visual Studio from trying to reconnect to TFS every time you open the project/solution.
I was surprise I couldn’t find any script to do so. Therefore, I had to build it myself and it came to me that others could use that script so here it is:
https://gist.github.com/baywet/bcbed5e52c59f4201e7c
You just have to call it passing the git directory path as a parameter (don’t forget to do it for every branch if needed).
Good luck migrating your repos!
PS: I also opened a discussion on whether or not Git Tfs should include this script, don’t hesitate to come share your thoughts about it https://github.com/git-tfs/git-tfs/issues/904