Can PGP Virtual Disk be configured to prompt for a passphrase every time a user needs to access it?
It is not possible to mount a drive and force Symantec Encryption Desktop (previously PGP Desktop) to ask for passphrase later at a time when the user accesses the disk.
Disabling password caching on PGP Desktop will prompt user for a passphrase at a time when the disk is mounted.
(it could be set to unmount a disk if it is not being used for a period of time)
Symantec Encryption Desktop