I dragged old backup files from my external hard drive to the trash (cleaning house). When I went to empty the trash, it took all night and then I got a message that some items were locked and asking did I want to remove them. Not knowing if it was OK, I said no and trashed only unlocked things. The trash is now still full of those old files. Can I trash locked files without affecting the hard drive versions (my apps)? They are just "backups" but I am a little leery of saying yes without being sure.