I created a new backup schedule and set the "Maximum Backups to Keep" option to 1. As a test I have it running the backup schedule every 5 mins. The "Maximum Backups to Keep" option is being ignored and there are multiple copies in the backup folder. Can someone please confirm if they can reproduce this problem?

Is there anything in the FMS event log that points to a problem?  FMS typically logs that it is removing an old backup?

Have you tried running a disk permissions repair?

I think I figured out what is going on. I am backing up a solution that has a container with external storage. Every time a backup executes it deletes the database files but leaves the previous backup folders along with any container content folders and their contents. It's a bit of a mess.