I\'m using TFS Preview (Team Foundation Service) with one of my projects with Visual Studio 2012. I\'m also using an on-premises TFS server with most of my projects. When I
I solved this issue by using the browser from within Visual Studio, View->Other Windows->Web Browser; Ctrl+Alt+R (or * Ctrl+W, W* in VS versions before VS2010) to navigate to the TFS page and log out of the wrong account and log back in.
For me, the issue was caused by using another live-id to unlock a windows phone for development. Somehow the credentials got cached, it seems.