Was the system encrypted before, and decrypted before an upgrade? If so, it is possible that there is some encryption data left in the boot sector. Basically, after encryption desktop is reinstalled, it will start looking for instrumentation data which points to the bootrecords. Since the previous encryption did not completely remove itself, the pointers are still there, pointing in the wrong places for boot data.
Also, particularly if using OS X 10.9.4, you must be on the latest release of our product (10.3.2 mp2)
Hopefully you have a backup of the data, as the following steps will clear all data from the drive. The process below has successfully remedied the first issue in all of my testing scenarios:
1. Boot to the OS X installer.
2. Open the terminal utility.
3. Run the following command in terminal:
fdisk -u /dev/disk0
4. (optional) Repartition the drive several times, using different numbers of partitions (3-5 times with 10+ partitions each time)
5. Format the drive with the desired number of partitions.
6. Install OS X or restore from backup.
7. Boot the system.
8. Update the system to the latest version of OS X if necessary.
9. Reboot the system.
10. Install Symantec Encryption Desktop version 10.3.2 mp2.
11. Reboot after installation completes.
You should not experience the circle wih a slash. Steps 3&4 both are methods of clearing the instrumentation data, so I included the second as optional. It couldn't hurt to do both.