the unmap working folder does not work for me because I can't pass the collection or owner parm to it. see the errors:
Path to Executable: C:\Program Files\Microsoft Visual Studio 10.0\Common7\IDE\tf.exe Command line: workfold /workspace:A23183-DM /unmap c:\data\build\ebiz\source Multiple workspaces exist with the name A23183-DM. Please specify the Team Foundation Server or qualify the name with the owner. Failed!
per the TF.exe docs... I should be able to use /collection:http://tfsdev:8080/tfs/defaultcollection