Most painless way to convert back to GUID partition?

countdrachma · #1 May 29th, 2009, 06:47 AM

I'm a bit unsure as to the best way to tackle this. I have a single partition on my Leopard install with that partition map scheme being a "Master Boot Record" as apposed to a GUID Partition Table (GPT). Not sure why it is not a GPT but I appear to have formatted it incorrectly when I installed it (as a replacement drive / upgrade of the original). In any case, I now need to change this partition system back to a GPT so that it will allow me to run firmware updates as EFI upgrades are dependent on a GPT partition.

My question is more or less what is the best way to accomplish this given it's going to require a reformatting of all my data in any case. I have it all backed up to a Time Machine backup on a Time Capsule but to reformat the drive would then mean I have to re-install the Tiger install, followed by the Leopard upgrade disks, followed finally by the restore from Time Machine.

Is there an easier way to clone the data perhaps, such as with a Carbon Copy Cloner disk to disk clone? Or would that "restore" then merely include the actual partition format back to Master Boot Record as part of the clone? (I suspect the clone includes the partition type). Any advice would be greatly appreciated! Are there any other options? Thanks in advance.

JeffCGD · #2 May 29th, 2009, 07:28 PM

Easiest solution would be to get a external hard disk, and partition and format it correctly with GUID and HFS+ journalled. Then use Carbon Copy Cloner or SuperDuper to do a full clone to it. Then boot from this to test it.

Now, while booted from it, fire up Disk Utility and reformat/partition your computer correctly to GUID/HFS+ Journalled. Now clone your install back off the external drive you are currently booted from.

That should work.

I'm actually surprised you managed to get your machine to install/boot on a disk you say is MBR. I didn't think you could do that. I thought that was for Windows only.

countdrachma · #3 May 29th, 2009, 08:11 PM

Thanks Jeff. That sounds logical and a good safe way to go about it as even if the MBP hard drive fails to reformat correctly etc, I would still have a fully functional version bootable off the external drive. What I'm not sure of though is that if you do a Carbon Copy Clone to a newly (correctly formated GPT external drive), does a Carbon Copy Clone copy the partition format as well? If so, when cloning the existing MBP MBR disk to the newly created GPT external disk, will the clone process make the external drive MBR as part of the process? I'm not really sure enough about how partition formats work and if they are susceptible to cloning. Any thoughts? Thanks again.

ElDiabloConCaca · #4 May 29th, 2009, 08:18 PM

Nope, a clone operation simply copies the data -- no formatting, no partitioning.

Carbon Copy Cloner may include an option to format the drive before cloning, but if it does, simply turn it off. I believe, if any option existed, that it is set to "off" by default.

countdrachma · #5 May 29th, 2009, 08:28 PM

Quote:

Originally Posted by ElDiabloConCaca

Nope, a clone operation simply copies the data -- no formatting, no partitioning.

Carbon Copy Cloner may include an option to format the drive before cloning, but if it does, simply turn it off. I believe, if any option existed, that it is set to "off" by default.

Thanks for the clarification. Appreciate both of your input guys. Gives me a way forward now!

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