I recently found myself in a situation in our TFS Source Control where I wanted to convert a main folder into a branch. However I was presented with an error message telling me that I couldn’t do this as a branch already existed below this folder. It turns out that a branch had previously been created incorrectly and then subsequently deleted. However, if you delete a branch its relationship remains and prevents you from branching its current parent.
I found the following blog post provided me with the answer. But more usefully it showed me the ‘show deleted items’ checkbox that gives you a much better historical view IMO of the Source Control structure. Maybe this should be the default view with the option to turn it off rather than on?
one more commit 
Thanks !