January 6, 2011
Mac OS X 10.6.5 and 10.6.6 are not compatible with the PGP Whole Disk Encryption.
If you are a WCMC user with a PGP-enabled Mac computer, do not upgrade to Mac OS X 10.6.5 or 10.6.6. Doing so will cause your Mac to be unbootable, requiring a restore using a Time Machine backup.