We have a couple of contractors who worked on our project before left. When they left, they didn't check in all the codes on their machine. I work on deleting some of the projects which have files checked out by them and are not used by anybody else now. I cannot do that because the TFS complains that some files were checked out by those contractors.
I googled around and found a simple solution in MSDN, the easiest way is to delete the workspace altogether:
Here is the exact command: tf worksapce /delete /server:servername workspacename[;workspaceowner].
The workspacename is normally the machine name.