Had a TFS folder hive mapped to "C:\Projects (TFS online)\ProjNameHere" and discovered problems with Xamarin due to the space in the name.
So, I deleted my old (obsolete) "C:\Projects" folder, renamed "C:\Projects (TFS online)" to "C:\Projects" and went into VS Source Control explorer to modify the workspace mappings. I did this and it acted like it worked, but it still shows the old path atop Source Code Explorer "Local Path:" and it re-creates the old projects folder. It seems woefully confused which is right, because when I go to unmap or remap again it has the correct (new) folder path.
Did some googling and tried deleting all the TFS cache files I could find, but no help there.