Mac OS X 10.5 Help
If you can’t install Mac OS X on a hard drive
If the Installer won’t let you install Mac OS X on a hard drive and gives as the reason “Mac OS X cannot start up from this volume,” the drive may not have the partition scheme that the Installer requires. The needed partition scheme depends on the type of processor in your Mac. The installer installs Mac OS X for Intel-based Macintosh computers only on drives with the GUID partition scheme. It installs Mac OS X for PowerPC-based Macintosh computers only on drives with the Apple partition scheme.
To check the external drive’s partition scheme, open Disk Utility, select the drive in the list, choose File > Get Info, and look for the “Partition Map Scheme.” If you can’t see the “Partition Map Scheme,” you may have selected the volume instead of the disk. (Drives are flush left, with their volumes indented to the right below them.)
You can change the partition scheme for the disk drive by repartitioning it. It’s OK to create only one partition.
To repartition an external drive so you can install Mac OS X:
Back up any important data on the drive. Repartitioning it erases all its data.
Open Disk Utility. If you’re in the Mac OS X Installer, choose Utilities > Disk Utility. Otherwise, double-click Disk Utility, which is in the Utilities folder of your Applications folder.
Choose the disk in the list, and click the Partition tab. If you can’t see the Partition tab, you may have selected the volume instead of the disk. (Disks are flush left, with their volumes indented to the right under them.)
Click Options and choose the appropriate partition scheme. Choose the GUID partition scheme for Intel-based Macintosh computers. Choose the Apple partition scheme for PowerPC-based Macintosh computers.
Click OK.
Set your other options, such as the number of partitions and their names. It’s OK to create only one partition.
Click Partition.
After the drive has been partitioned, you can install Mac OS X on it, and then restore any data you backed up.