Symantec Encryption Desktop (formerly PGP Desktop) has an option as part of the installation where you can click on "Customize" and check or uncheck the option for Symantec Encryption Desktop or Symantec Drive Encryption. The problem is that both options are grayed out and checked and you cannot uncheck them.
Workaround (only works on Symantec Encryption Desktop10.2.1 MP5: use at your own risk)
Don't follow these instructions on 10.2.1 MP4 or other non-10.2.1MP5 versions until you contact Symantec Encryption Support to verify that it's compatible
Mac OS X 10.7 or newer
Symantec Encryption Desktop 10.2.1 MP4 and newer