I have a MBP Retina display, I just bought a Lacie Little Big Disk (1TB) Thunderbold drive. My old computer is a MacBook Pro running Lion (Intel based MBP) Since my old MBP doesn't have any thunderbolt connection I booted the MBP into disk mode by holding the letter "T" - I connected a Firewire 800 cable to my retina display and the drive was mounted on the desktop. I used SuperDuper to create a mirror image of that internal drive to my thunderbolt drive. When I reboot my Retina MBP I hold the "option" key and I see the drive I've mirrored. When I selected I get a circle with a slash through it right in the middle of my screen. Do not pass go, do not collect $200... I've also removed the RAID that comes with the Lacie Drive and have made the backup copy to one of the two drives in the Lacie with the same problem... Any help would be greatly appreciated Is it because the bootable drive isn't running Mountain Lion? What am I doing wrong?