[bobcola]

I can't get my Mac to boot from an external drive. Two different drives, in fact.
I have backed up my iMac's HD to 2 external drives - one is a WD Firewire 800 drive, the other is a Maxtor USB2 drive. I cloned the drive with Carbon Copy Cloner and Super Duper and I have a copy of each on each drive. That's four separate clones on four separate partitions. I formatted the external drive partitions using GUID, Mac OS extended journaled. Disk utility sez that they are bootable. I restart the computer holding down the option key. The cloned drives appear. I select the cloned drive I want to boot. I wait and wait and wait and ultimately the computer boots up with the internal drive, not the cloned drive. This is making me crazy. I even cloned Snow Leopard disc to an external hard drive partition and it won't boot to that either! What have I done wrong??!!

[Simon]

Sorry to hear, but you have become just another victim of CCC and SD. You're not the first person to experience that their "bootable clones" turn out to be neither bootable nor a perfect clone.

The solution to your problem is to ditch both apps and instead use the free utility from Apple that's built right into OS X and actually works. It's rock solid, it's very fast and it's of course free. You'll find it on every OS X installer DVD and on every OS X installation.

/Applications/Utilities/Disk Utility > Restore.

Select erase destination to get a bootable clone in block-copy mode (fast!).

[bobcola]

Thanks, Simon. I was leaning in that direction as the next move.