[Solved] Rekordbox won't delete data on USB

I have deleted everything in my USB in both Rekordbox and in Finder (using a mac). no files shows up in the regular usb drive, and no songs shows up when it's connected to Rekordbox.

However when I try to sync my new library it says my USB is full. I realize there is all of the hidden data of my Rekordbox songs still on my USB. I Just can't figure out how to clear that out. I just want to completely wipe it. Help! Thanks.