To repair your startup disk, you must startup from your Mac OS X Install disc or another drive on which Mac OS X is installed. You cannot use Repair Disk to repair your Mac OS X startup disk � for example, Macintosh HD � while your Mac is started up (booted) from such.Keep in mind the following key points about Repair Disk: All hard disks have one or more volumes or partitions.
A volume, also known as a partition, is section of a physical hard disk which, from the perspective of the operating system, works like a separate disk.
The directory is analogous to a combined address book and road map to where data is stored on a disk or volume. Repair Disk verifies and, if problems are found, corrects issues with the directory on a disk or volume. It is a subset of the more comprehensive information on these topics from our book, Troubleshooting Mac OS X. This FAQ provides a brief overview of the Repair Disk and Repair Disk Permissions functions of Disk Utility in Mac® OS X. The Repair functions of Disk Utility: what's it all about?
