Mac OS X’s Disk Utility is an underused and often neglected tool. It is a multi-talented tool, that can be used for its obvious purposes, working with hard disks, but has some not so commonly used talents. Here is a brief overview of what Disk Utility can be used for.

For some, disk utility can actually be hard to find. To open disk utility go to the Utilities folder, which can be located within your applications folder. A shortcut to launch the Utilities folder is by pressing Command-Shift-U. Once disk utility is launched you should see a window with the title “Disk Utility” at the top. All of your hard disks and external hard drives should appear in the left hand side of the window. By clicking each drive you get an overview of information about each disk, such as mount point, format, number of folders and files, capacity, available and used space. Unfortunately you will not see a detailed breakdown of used space but you can use another program for this such as disk Disk Inventory X.

If your disks are experiencing issues, disk utility can sometimes provide a bit of disk magic by repairing permissions, which can be the root of many problems on a Mac. To understand disk permissions, OS X immediately appoints different files on your computer an owner and chooses the degree of accessibility these files have. The Mac then writes a hidden file in /Library/Receipts that instructs the computer what the permissions should be. After many installs, system upgrades, etc, these permissions can become affected. By “repair disk permissions” you tell your computer to look at the hidden permissions file and locate any issues. To do this, click on the disk to the left which is experiencing problems, and then select the “First Aid” tab. Then, click “Verify Disk Permissions,” which will run a check to see if there are any problems. If problems are found you can then click “repair disk permissions” which will correct the errors.

The other areas in Disk Utility are Erase, RAID, and Restore. Caution, Erase can clear all the data on a drive, so be careful if you are in this tab. RAID, which stands for redundant array of independent disks, here you can setup multiple drives for either a Mirrored RAID, used for data backup or a Striped Raid, used for performance. Mirrored RAID copies all of the files of one drive onto another. The striped RAID creates files in organized segments or “stripes” and is said to enhance performance. The Restore feature copies the complete contents of a hard drive to a different location or allows you to “restore” from a backup file.

This is the very basics of Disk Utility. More experienced users use Disk Utility for it’s other talents such as to partition drives and burn bootable system discs. Disk utility is a very simple tool to use for disk related problems and repairs.