If you are unable to boot a Mac OS X system which is Drive Encrypted (previously PGP Whole Disk Encrypted), you can use the Target Disk Mode feature to access the disk for data recovery.
Target Disk Mode allows you to boot a Symantec Drive Encrypted system and use the Terminal command line tool for troubleshooting.
Target Disk Mode allows for a Mac OS X system to boot to another disk or system to access the other disk. This can aid in recovery of data on a Mac OS X system. This includes using an external USB drive, another Mac OS X system, or possibly even a network drive. When booting with Target Disk Mode, the alternate system is accessed as a "slaved" drive.
This is useful to troubleshoot encrypted drives.
After booting to the targeted disk, Terminal can then be used to troubleshoot an encrypted drive.
External USB Drive
Plug in the external USB drive and boot the problem Mac OS X system by holding down the Option key. A window with the main boot drive and external USB drive is displayed.
Select the external USB drive and boot the system. The system will then load normally using boot the external USB drive instead of booting to the main boot drive. If Symantec Encryption Desktop is installed on the external USB drive, you can troubleshoot the disk from the Terminal command line.
Two Mac OS X computers
If using two Mac OS X computers, connect the two computers via FireWire and while booting, hold the option key down. Once the screen displays the two drives, boot using the other Mac OS X computer. The system will boot off of the other Mac OS X computer, but will allow access to the problem Mac OS X system as a "slaved" device.
For more information on using FireWire Target Disk Mode, click here for an Apple Support article.
You can then troubleshoot or decrypt the disk using the pgpwde tool from the Terminal.
To decrypt a an encrypted drive, run Terminal from Applications > Macintosh Utilities. From the command line, type:
This will list the current disks on the system. Check to see which disk number is the problem system. Boot disks are typically labeled "disk 0".
Run the following command to see if a drive is encrypted:
pgpwde --status --disk 0
This returns the status of a disk. If a disk shows a highwater mark, this indicates the disk is encrypted or shows the amount of sectors that are encrypted.
To access the encrypted disk having issues, type the following command:
pgpwde --auth --disk 0 --passphrase "passphrase here"
This will unlock the encrypted disk and allow access to the disk. It is then possible to copy data from the problem disk to the other Mac OS X computer if necessary.
To decrypt a drive, issue the following command:
pgpwde --decrypt --disk 0
If any of the above commands cannot be found, even though Drive Encryption is installed on the Mac OS X operating system, it may be necessary to run the commands from /usr/local/bin with ./ in front as in the following example: