It seems that, for some reason, a workspace hasn't been created on the local drive of your machine or, if it's there, something is problematic in how it is mapped or created.
Check out the following and see if any of this helps.
https://blogs.msdn.microsoft.com/granth/2008/07/22/tf-exe-unable-to-determine-the-workspace/
I tried the steps from the link and also deleted the cache from -- %LOCALAPPDATA%\Microsoft\Team Foundation\.
Still No go.
Time to contact support directly, I guess.
Solved!
Figured out that I was running the Team Explorer from Visual Studio 2015.
Downloaded the stand-alone Team Explorer 2017 version and that resolved the issue.
Regards,
Nimith
