I used the free version of Superduper to create a clone image on an external firewire drive but it doesn't seem to work. The cloning process goes through to completion ok, apparently, but I can't get the computer to boot up from the external drive. I tried holding down the option key before I even press the start button and also right after I press the start button, but in both cases it boots from the Mac hd and I never get an option to choose from which source to boot. Can anyone please advise on what I may be doing wrong? Thanks for any help.