Fix Solution and Code Project Bindings
In rare situations, to ensure that version control features in Solution Explorer can function correctly, you might need to unbind and then bind your solution and code projects. You don’t need to perform this procedure unless the system prompts you to do so.
You must be one of the Contributors for your team project. See Team Foundation Server Default Groups, Permissions, and Roles.
To repair your solution and code project bindings
Choose File, Source Control, Change Source Control.
The Change Source Control dialog box appears.
For each solution or code project that appears in the Change Source Control dialog box:
Read the value in the Status column. If the status is Valid, skip to the next solution or code project. If the status is Invalid, then continue to the next step.
Choose Unbind (if shown).