OS X Mountain Lion Bible

Using Disk Utility

When you're setting up or troubleshooting disks, you use OS X's Disk Utility, shown in Figure 31.1. Among its capabilities are formatting disks, checking (verifying) and repairing disks, mounting and unmounting disks, converting disks into disk images, and recording (“burning”) disk images to CDs and DVDs.

To run Disk Utility, launch it from the Utilities folder, which you can get to quickly by choosing Go⇒Utilities or pressing Shift++U.

Note

Mounting means making the disk appear in the Finder; unmounting means making it invisible but still connected. (Compare that to ejecting, which both unmounts and disconnects the disk so you can unplug it.) A disk image is a file that contains all the contents of a disk, so you can move it to another disk or to a removable medium such as a recordable DVD.

Note

In the Sidebar at the left of Disk Utility, the drives are shown aligned to the far left, while the disks (for a multiple-disk drive) and partitions for each disk are listed indented below the drive name.

Checking and fixing disks

The most-used part of Disk Utility is the First Aid pane, where you can check a disk's health and try to repair it. Select the drive, disk, or partition from Disk Utility's Sidebar, and click Verify Disk to check it or Repair Disk to both check and repair it. You also have the options on some disks to verify and repair the disk permissions, ...