Currently, Symantec Drive Encryption (previously PGP Whole Disk Encryption) is compatible only with 512-sector size and not 4K Native sector size drives. If the drive supports 512 byte emulation mode (commonly referred to as 512e or Advanced Format) then Symantec Drive Encryption should be compatible with the drive.
Each of these commands will be ran in a command line windows in order to help identify whether a drive is using 4K Native, or 512/512e:
Start > Run > cmd and hit enter.
Sample output from the above command:
diskutil info / | grep "Block Size"