Recently, while trying to synchronize with my Visual Studio Online git repository, the Visual Studio Git plugin started displaying the error “URI formats are not supported” while attempting to execute a pull operation. This appears to be an issue introduced with Update 2, and at least from my own experience only appears to be affecting Pull operations.
This issue appears to be manifesting in my case due to either a web application or WCF service application that I added to my solution and synchronized to the repository. If you’ve done something similar, you’ll probably start seeing this error as well. After this error occurs, push synchronizations will continue to work, but attempting to pull changes or use the ‘Sync’ operation on the remote repository will fail with the error message.
The issue has been reported to Microsoft back in May and a few workarounds have been posted, including a suggestion to use another tool like SourceTree to execute your repository synchronizations.