Mac OS X (Intel)--Bootable Drives Need GUID Partition Scheme

as we noted yesterday in our Hands-On Report on the MiniMate used as an external bootable FireWire drive for our 2GHz iMac Core Duo. With one exception that we discovered, an Intel-based Mac can only install Mac OS X on a disk with the GUID_partition_scheme. This partition scheme is a new step for Mac users.

If you have a new Intel-based Mac and reformat your internal drive, make sure that when you use Disk Utility to do so that you click on the "Options" button under the "Partition" tab and select the GUID_partition_scheme. Why? Because the partition scheme needed on Intel-based Macs is the GUID_partition_scheme.

In addition, hard drives that you buy that have been formatted for the Mac will most likely have been formatted with the Apple_partition_scheme. They need to be re-partitioned with the GUID_partition_scheme before your Intel-based Mac can install Mac OS X on it. The default partition scheme in Disk Utility on Intel-based Macs is the partition scheme currently installed.

The one exception we have found is that Carbon Copy Cloner can clone an Mac OS X (Intel) startup drive to an Apple_partition_scheme drive and it will boot an Intel-based Mac. However, Mac OS X (Intel) still cannot be installed on the drive without re-partitioning it.

Note that the Apple_partition_scheme works with Intel-based Macs on disks that do not need to have Mac OS X (Intel) installed.

Our main question is why has Apple not made the GUID_partition_scheme the default partition scheme in Disk Utility running on an Intel-based Mac? The second question is why has Apple hidden the required partition scheme selection two levels away under a button labeled "Options" in Disk Utility? Hopefully, Apple will fix this in a subsequent version of Mac OS X (Intel). More... [Bill Fox]