I have had this happen on a few of my machines as well. McAfee will probably tell you to de-crypt the disk using EETech and then re-encrypt the disk. I have had some success with performing an Emergency Boot from the EETech Standalone disk.
I have had similar issues with this error, using the EETech CD (Stand-Alone) and emergency booting into the operating system.as mentioned above, has worked. Once in the OS, after the e-boot, I right click on the McAfee agent icon and select quick settings and then show endpoint encryption status and see that the system state is set to recovery. I do a couple of collect and send props via the agent status monitor and once the system state goes to active, I am able to re-boot the system without issue. On a couple of occasions we have had to perform a token recovery for the user but this has worked as Kink80 mentions above.
This appears to be an error caused by Endpoint Encryption. Please ensure to post your question to the right team, in order for us to be able to assist you.