I have BESR 8.53 editions for servers and workstations.  On both, I have the "automatically optimize storage option" enabled on Manage Backup Destination.

On both editions, if I choose an external drive to backup to, why do I periodically run out of space on the target drive and have to manually delete old backups in order for everything to proceed.? 

The "automatically optimize storage" is supposed to "delete old recovery points and and limit file versions to reman within threshold without prompting".

Is there a step I'm omitting, or something I'm misinterpreting?

Thanks.