We are using Acronis Backup & Recovery Advanced Server SBS Edition. Our backup schedule is a full image on saturdays then diffs on mon-fri. All of these are going on to usb drives that are changed weekly. The problem is that the old backups are not deleting. The backup errors out say the drive is full. I have setup a retention policy of 6 days so in case the drive isn't change it will continue to work. But it doesn't delete any of the old backups. Please help!