1) Check your edit folder and ensure nothing is in there open for edit.
If you recently had a crash and chose use anyway, you may have bits left over. I've had that message a few times when I ran a database repair after doing that.
2) There aren't any extra files in there and the database is confused.
I've had this too and I think this is related to a mix-up in the database. The assets.tdx contains records that reference the content data files. If there are duplicate records, I believe this will create that message. The way to check this is to run an EDR and see if that cleans that up.
No I am not talking to my self, it is a guy who got my numbers to get them using my name, and I have to tried get rid of him doing it. He lives in Beaver, PA also. I want to get a hold of him. I told Tony but he never got back to me.