Ok, I've followed the documentation for migrating from one ePO server to another with encrypted users and we went over it as a group to make sure we didn't miss anything. Problem is that none of the users are able to login with pre-boot authentication enabled after the transfer. Could really use some guidance here as it is cost us a ton of time and many headaches.
Switched from ePO 4.6.8 to 5.3 with EEPC 7.1.3
Likely the users were removed. Look in the MfeEpe.log and see if the users were removed after the transfer. How did you run the ePO Web API command to enable system transfer?