GUID problem with Leopard, and a fix.

So after almost a month of Leopard being released, along with a new update to 10.5.1, some users have been having problems with the install of their copy of Leopard. A handful of users are getting a message saying the following:

You cannot install Mac OS X on this volume. To enable installation on this volume open Disk Utility from the Utilities menu and repartition this disk as ‘GUID Partition Table’. Note: you will lose all data on this disk by repartitioning it.

Now, if you have an Intel mac, it should have come already partitioned as GUID, but if you have used Disk Utility to erase your drive, or for any other reasons, it may have partitioned your drive to Apple Partition Map by default. Note: This will also only be a problem with Intel machines, as PPC machines require Apple Partition Map to boot Leopard. Hopefully this will help those of you with important data, that can’t afford to just erase their drives.So if you have found that you are having problems installing Leopard for this reason, here is what you can do.

I know there are other methods, but this is what we have found to work, so here it goes.

Step 1a: If you have data that is important, you will need to create a backup of your data, that can be done in multiple ways, but we would recommend if you have an external drive to use Disk Utility to either create a disk image of your internal drive, or if you don’t need the data on the external drive, you should be able to just restore your internal drive to your external drive using the “Restore” tab in Disk Utility (You will need to have an external drive at least the size of your internal for this option). All of this will need to be done while booted off of your install DVD (hold “c” key when you power on your machine with the disc inserted).

Step 1b: If your data is not important, just boot off of your install disc, as noted above, and start up Disk Utility. (If this is your step, then the rest of the install will go quite simply.)

Step 2: You should now have your data backed up if needed, and ready to repartition your drive. Just select the “Partition” tab with your internal hard drive selected. From here you will select “Options…” towards the bottom and then choose “GUID Partition Table” and hit OK.

Step 3: Now click “Partition” on the lower right and it will set you up with a fresh GUID partition. Now you can continue installing Leopard by selecting your internal drive from the installation assistant. Below are steps to get your old data that you backed up back onto your newly installed Leopard OS.

Step 4a: If you chose to restore your internal drive to an external drive using Disk Utility, you have an exact replica of your internal drive, so once Leopard is done installing it will reboot and startup into the Setup Assistant. From here it will ask you if you want to retrieve your data from another mac. You will select this option with your external drive plugged in. It will then take your user settings and programs and migrate them to your internal drive. At this point you should be set up to go.

Step 4b. If you chose to just select particular folders and applications to back up, you will need to go through the setup assistant and enter your personal information in. Once you see your desktop you will be able to just copy the data from your external drive (or CD/DVD if you decided to back up to a disc) and place it’s respective directory or folder. Then you will be good to go.

I am sure there are plenty of other ways to do this, but we have found this to be a pretty thorough and effective way to safely get your data from an Apple Partition Map Intel drive, to repartition it and restore the data.Thanks.

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This entry was posted on Tuesday, November 20th, 2007 at 9:48 am and is filed under Author Posts. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

One Response to “GUID problem with Leopard, and a fix.”

  1. mosk22rte Says:

    January 12th, 2008 at 4:55 pm

    Thanks for posting this! I have an Intel MacMini and had removed the internal drive and upgraded to an external SATA drive, which I had previously formatted as an Apple Partition. Your description above saved me a bit of head scratching after Leopard refused to install. Thanks!

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