Why do I get the error, "Item has already been added. Key in dictionary" when checking a renamed file in from Visual Studio?
This issue usually occurs when checking in files through the Pending Check-ins dialog in Visual Studio.
This is a known issue with how the dialog gets refreshed in the 2005-2006 (9.x) version of the Visual Studio integration and has been fixed in the 2008 release of it. This version is scheduled to be released in Q1 2008.
Please check the following integrations page for details on whether or not the 2008 VS Integration is available yet:
A workaround for the current version is to perform the check-in
via the pending check-ins dialog once then delete the contents of
this dialog then close and re-open it.