Thanks for you advise, however I'm still at a loss.
Disk is encrypted by Passphrase.
Do not save my passphrase - checked.
Mount at startup - unchecked.
Unmount when inactive for X min - unset.
Disk was still mounted at system restart.
Allow PGP disks to unmount even while files are open - checked.
Unmount when computer goes to sleep - checked.
Disk was still mounted at system restart.
FYI - I have been using PGP encryption for many years, long before Symantec took it over and I have never had this issue on another Windows OS or version of PGP.
Thanks in advance for any further ideas...