It can be a challenge to move a project from one TFS source control to another. This is because TFS has the concept of workspaces. These workspaces are generally behind the scenes so you do not know they are being created. If you try and move a project that is currently associated with a workspace it will complain when you try and connect the same project with a new source control. The first step is to remove the workspace binding. To find the workspaces go to: File>Source Control>Workspaces....