My second internal HDD think it's a time machine backup drive. I can create copy and move files, but cannot delete. whenever i attempt to delete anything, it tells me "The operation cant be completed because backup items cant be modified." I cannot unmount the disk to repair it (although i did a disk verify and it was OK) Should i just go ahead and restore from a few hours old time machine backup? I don't want to because it's late and i have a plane to catch tomorrow morning.