I'm happily crunching away on my new machine setting up Visual Studio and such. I've mappped in a workspace using TFSPreview to my c:\dev drive. Somehow I accidentally wind up with a second mapping to my c:\dev drive. Attempting to pull down any files results in the following wonderful error message:
In Source Control Explorer, the workspace shows as "not mapped" but when I try to set the map, up comes the dialog of no use as seen abovwe.
I attempted to go the long route in the Visual Studio IDE. File / Source Control / Advanced / Remove Workspaces. Again, up comes the dialog of doom, and again I'm left with no route to remove or modify the offending workspace.
RESOLUTION: I channel my inner Esteban Garcia (one of my favorite Florida TFS gurus) for starters and open the "VS2012 x64 Native Tools Command Prompt". Then type in "TF Workspace". Remove the offending entries. If you get an error message that it can't resolve the workspace, type "TF Workspaces" on the command line to find a list of viable edit workspace targets. One you've removed the workspace you can re-add one in for a different local location and avoid the conflicts.
Posting the full error message for the SEO gods in the hope this helps someone else out in a sticky situation.
Microsoft Visual Studio
Multiple identities found matching workspace name
Please specify one of the following workspace specs: