We are also having this issue at my company, FATAL ERROR: Cannot decrypt Root partition. We have 3 Optiplex 3000 machines that are getting this error. I was told by a Dell Tech that it had to do with the order in which we are installing our files. We use the WMS to deploy packages. We were told that we need to setup different groups in our WMS to deploy the updated OS firmware, then BIOS and then Apps, instead of putting them in a group with the newest packages available.