Keep Team Foundation Server from connecting automatically upon opening up Visual Studio 2012.

1. Type "RegEdit" at the start menu to bring up the Registry Editor in Windows 7.
2. Computer > HKEY_CURRENT_USER > Software > Microsoft > Visual Studio > 11.0 > TeamFoundation ...should be right-clicked upon and then "DWORD (32-bit) Value" should be picked from the "New" submenu of the menu which appears.
3. Change the name of the new item to "AutoLoadServer."

 
 

The above comes from:

1. http://stackoverflow.com/questions/13816331/prevent-visual-studio-from-connecting-to-team-foundation-server-on-startup
2. http://support.microsoft.com/kb/136393