A Microsoft file hosting and synchronization service.
I wanted to respond to the person who just commented but I can't directly reply.
Anyway - I emailed Microsoft Support about this, and they had me record my actions of trying to delete the file and send them the file and they did some sort of patch. I honestly don't know much about that part, but you could reach out to the Microsoft support email and see where it goes. The file was still in my shared folder, but I generally let it go because I was able to get my account secured again. I just "hid" the file and it finally worked (it didn't use to), but I don't know if that actually removes the file from being in that shared folder.