The path is already mapped in workspace error.
The path x is already mapped in workspace.
Error The path is already mapped in workspace. 
TFS 2010 Mapping Issues. I’ve lately reinstalled my TFS 2010 and after do so, I encountered an extremely annoying error:
“The path is already mapped in workspace”.

I searched for almost everywhere, I tried changing Visual studio files and nothing.
It was only then I found out where was the problem – in my Team Foundation Cache.

After realizing that – the rest was fairly easy.
Simply go to this folder: C:\Users\{UserName}\AppData\Local\Microsoft\Team Foundation\3.0\Cache and delete all that’s in the folder.

This was a rather quick solution to a problem that was keeping my mind busy 🙂

Hope it helped,

Elad Shalom,
CTO at ITweetLive.com