When you see files 'expiring' during a backup, it means that the active
copies of the files in the ADSM database are being changed from 'active'
to 'inactive' files; the physical file is not getting  backed-up again.

If a file is deleted from the local machine between incremental backups,
ADSM will 'expire' the file on the second incremental backup to maintain
the 'active' copy of the filespace on ADSM.  In essence, ADSM detects that
the file is no longer on the machine, so it removes it from the 'active'
database.

Jim Smith / ADSM Technical Support / San Jose