"Remove Mapping" hassles in TFSPreview

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
Remove Mapping
Multiple identities found matching workspace name
Please specify one of the following workspace specs: