I have recently purchased a Western Digital 1 TB My Book Studio external drive, for backup for my 20 inch imac Intel Core 2 Duo, 2.4 GHz (mid 2007), 3 GB ram, 320 GB internal drive, running OSX Snow Leopard 10.6.8.
I have formatted the external drive, GUID partition, and installed Snow Leopard on it. The drive mounts in all modes (Firewire 800, FW400, and USB).
It shows up as a bootable drive in the System Preferences->Startup Disk pane. However, I cannot get it to boot in any mode - I get only a blank white screen on startup, and after waiting 15 minutes I turned off power and restarted pressing the option key; the white screen then showed only the internal imac drive. Then the desktop still shows the external My Book external drive on the desktop.
The Western Digital website shows this drive to be bootable on Intel Macs.
How can I get the drive to boot from this external drive?
Thanks in advance for any help.