solution: This error usually due to workspace getting corrupted especially when local workspace are configured. This error doesn’t allow you to view the source control explorer. To solve this and to re-use the same workspace, you have to rename the $tf hidden folder which will be created at the root of your local workspace mapped folder. * Pls don’t use this method if your code is merge from the branch to the trunk but not yet check-in to the trunk.
For further references: