"Locked Track" issue is killing me!

I have an open project on GarageBand and there is suddenly a new "Master" track opened in it, and when I try to delete it, I get the "All selected tracks are locked and can’t be changed." message. Weirdly enough, when I actually LOCK the track, the "Delete Track" option in the right-click menu becomes clickable, but still tells me the same thing. When it's unlocked, I don't even have the option to delete it, the entire menu is greyed out. How do I delete this track??