I am having an infuriating problem.

1 workstation on the network constantly has problems validating
credentials against edirectory when the workstation is locked.

Whenever the user locks their workstation and then returns, they get an
Error -1497 when trying to unlock their machine.

They are able to unlock using the Windows credential, and many days life
is fine. However, this workstation is the backup administrator's
workstation, and lately backups have a 50/50 chance of running. Having
been on the merry-go-round with Symantec, I am beginning to wonder if the
credential issues are affecting the backup every night?