I have installed ARCserve 6.61 on NT4 Server. I was using ARCserve2000 and removed it for the older one. When I set the Backup Schedule for Mon-Fri (Differential, Full Backup on Friday) the media pool was created properly and the job was validated. When the first job ran (Wednesday) it performed a full backup instead of a differential. Why is this? Is this because there was no Full Backup to compare the differential to? Thanks