Hidden workspaces in TFS

I've ran into an issue where I had to switch user under which i was connecting to TFS. Somehow workspace from my previous account was still present in the system and checking out solution to the same folder under the new workspace ended up with errors.

There's a tool called Team Foundation Sidekicks which can help to resolve this situation. You can view all workspaces, modify them, etc... Awesome tool, free one too!