I have backup 8.5 running on Windows NT.I have purchased 19 DAT tapes in the hope of running the Grandfather / Son rotation scheme.I used the wizard to set this up and first started on a Wednesday with a normal backup.When I put this tape back in on the Friday as instructed it wouldnt append.This also happened on the Wednesday tape.I looked at the properties for this media and it said "overwrite 4 weeks" and "append 6 Days".That is correct isnt it.It wouldnt append to the media so i had to change the overwrite period to 6 days also.It then worked but surely this defeats the object of automatic backup.Can you offer any advice.Thanx for your help....