My libraries folder contained a libraries folder which contained a libraries folder which......
and so on for over 300 folders.
I tried deleting it and it came back.
I tried going to the command line and trying to rd it. It came back.
I finally tried deepremove from:
https://deepremove.codeplex.com/releases
worked great. (995 folders deleted)
I make a new libraries folder and this one seems well behaved.