You can set the AutoLoadServer registry key to 0.
Go to Team Foundation Key
HKEY_CURRENT_USER \ Software \ Microsoft \ VisualStudio \ 10.0 \ TeamFoundation
Add an AutoLoadServer registry key of type REG_DWORD

Set to 0 so that VS does not automatically connect to TFS at startup

Or create a * .reg file with the following:
Visual studio 2010
Windows Registry Editor, version 5.00
[HKEY_CURRENT_USER \ Software \ Microsoft \ VisualStudio \ 10.0 \ TeamFoundation] "AutoLoadServer" = dword: 00000000
Visual studio 2013
Windows Registry Editor, version 5.00
[HKEY_CURRENT_USER \ Software \ Microsoft \ VisualStudio \ 12.0 \ TeamFoundation] "AutoLoadServer" = dword: 00000000
Visual studio 2015
Windows Registry Editor, version 5.00
[HKEY_CURRENT_USER \ Software \ Microsoft \ VisualStudio \ 14.0 \ TeamFoundation] "AutoLoadServer" = dword: 00000000
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