I did this myself 1 week ago.
Go into DU.
Select the *external* (be careful on that) disk in the left list ... NOT any partitions on the disk
Select "1 partition" in place of "Current" (or two, if you want, but backups should be 1 partition).
Under "options" select "GUID"
Name the disk as you wish.
That will give you a GPT partitioned disk to use for TM or CarbonCopyClone.
You will lose the LaCie manuals on the disk, but who cares ... internet will have those and they are not needed for me at least anyway.
I was thinking of that very failure a few minutes ago ...
Finder > Applicaions > Utilitites > Disk Utility
Also follow https://discussions.apple.com/message/16249731#16249731to find another thread where "Stress Test" attached a pretty picture ...
This is easy enough to to, but ALWAYS remeber that until "Apply" is pressed, the RED bubble in the window will cancel the disk changes.
Walk through it slowly as you need, but save "Apply" until you are comfortable.
When you have accomplished that, re-post and "PowerPC" explanation wlll be provided.
Thanks for the instructions, I'm about to try this with a new LaCie minimus 1TB drive on a MacBook Pro running OS 10.7.2. However, I was planning on creating two partitions; one for backup (Time Machine) and the other for general storage. Could you explain why "backups should be 1 partition"? Is my plan to have 2 partitions on the drive a bad idea?
Your backup is the main defense against losing critical information.
You want as much space available (1 TB will vanish quicky as multiple copies of your files accumulate, which is the way it is suppoed to work).
Also ... why "play around with picture files" on the same disk that is your "catastrophe recovery? Keep your backups separate. Just keep them separate.
Also, download CarbonCopyClone instead of using TimeMachine. CarbonCopyClone makes a fully bootable copy of your startup disk. That means when (al disks die eventually) the main internal disk has issues, you simply boot off that clone and you have a fully functional OSX to perfrom necessary repairs to the internal OR to clone that image back onto your new internal if it really dies.
Thanks for the information. Although I don't "play around with picture files" (perhaps you are confusing my post with another?), I do like the philosophy of keeping the backup just for backup. Storage is cheap. I'll track down CarbonCopyClone right away.
thanks for keeping your responses understandable for new users.
As a follow up, see the archived discussion on the Carbon Copy Cloner discussion pages, with suggestion for a partitioned disk for TM and CCC. Also has comment by Mike Bombich (CCC master). So keep an external drive exclusively for backup, but can do both TM and CCC on same drive: