using adobe audition back up files

How are we supposed to help? You've given us nothing here to go on at all, so I'm going to try a guess: After you'd saved these files, did you check them at the time to see of they played correctly? Cloud backup is notorious; saving audio direct from Audition to a cloud drive is almost guaranteed not to work - the file saving process assumes that the drive is available all the time, and since it's at the other end of a piece of wet string, it's hardly going to qualify. The only safe way to make cloud backups is to save the files locally, and then do a file transfer to the cloud, not a save. And the same goes for the files on your local(?) drive; did you check them when you'd created them?