I'm tearing my hair out here! I can't figure out why encryption fails on the Dell Mini 12 laptops.
It seems to install the preboot and begin encrypting fine, then after a restart or two, the machine POST's then never gets to the preboot screen. I've tried letting the whole drive encrypt, and I've tried restarting the machine as soon as the software was installed, and I've tried disabling a few options in the machine group on the server but nothing seems to want to work!
There don't seem to be any options for changing the operation of the hard drive in the BIOS! Then again, it's A02 and I've noticed that there's an upgrade to A04... I'll upgrade and see if the options appear.
I had similar issues a while back on some machines in our environment. Look in the BIOS for anything relating to your SATA drives. For me, it was under SATA Operation. We had IRRT selected, instead of AHCI like it should have been.