Russell,

Had some similar problems on a few machines here and found that after doing
a manual GUI backup of all the drives they started to back up again.  (This
assumes that there have been no changes to the NTFS file system.)  It looks
as if ADSM simply forgot about the drives.  Hope this works for you.

Regards,
Mark.

Mark Reschke
Information Technology Services
University of Melbourne

mailto:M.Reschke AT its.unimelb.edu DOT au