XDA Basics: What is Disk Utility on Mac and What can it do?

Apple’s macOS is extremely popular due to its intuitive interface and relative ease of use. In addition, Apple designs attractive hardware that consistently puts some of their options on our list of the best laptops you can buy. While your Mac likely runs well most of the time, there’s the occasional need to troubleshoot potential problems. When you need to diagnose and repair issues with your hard drive or create a disk image, Disk Utility on Mac is the app for the job.

Disk Utility main menu on MacDisk Utility main menu on Mac

Disk Utility is an app baked directly into macOS and located in the Utilities folder. The most common use of the Disk Utility app involves checking for errors on your disks or volumes. This tool is also helpful in repairing issues with your disks if any are found. Many users never explore Disk Utility beyond this simple use-case. As we will see, Disk Utility on Mac offers a plethora of other powerful tools.

Check for and repair errors on your disks and volumes using Disk Utility

Checking for errors within your disks and volumes is a breeze with Disk Utility. If you’re experiencing multiple app crashes, corrupted files, or sudden reboots then this is a great option to explore.

first aid dialog box on Disk Utility on Macfirst aid dialog box on Disk Utility on Mac

To check and repair a disk, you need to run First Aid on each volume and container on the storage device in turn, then run it on the storage device itself. After running First Aid on each volume and the disk itself, you’ll receive a report of any errors found. Typically, any issues found are automatically repaired. If you receive an error message, instructions are provided to either reformat the disk or replace your hard drive if it cannot be repaired.

Format and manage volumes on physical storage devices using Disk Utility

Before diving into this popular use of Disk Utility, it’s important to understand the difference between a disk and a volume. These words appear frequently in the Disk Utility menu. The term “disk” refers to the physical hard drive itself. A volume is merely a formatted portion of a disk. Since a volume is a subset of the disk, if you erase the disk then all volumes contained within it are also deleted. On the other hand, you may erase a particular volume without erasing the entire disk.

partition menu in Disk Utility on Macpartition menu in Disk Utility on Mac

In order to distinguish between the idea of erasing a volume and erasing a disk, we often say we are formatting the disk. This concept is important because Disk Utility offers the option to erase volumes and the ability to format a particular disk. If erasing a volume is what you’re interested in, there are both basic and secure options. Formatting an entire disk takes longer than erasing a volume, but this option is also available in Disk Utility. Note that if you would like to format your Startup disk, then you must boot into macOS Recovery mode and choose Disk Utility from the menu.

Create a disk image to encrypt folders using Disk Utility

A disk image is a single file you can use to move files from one computer to another or to back up and archive your work. Disk Utility allows you to create new disk images for either purpose or even use the image to encrypt folders on your Mac.

creating a disk image from a folder for encryption in Disk Utility on Maccreating a disk image from a folder for encryption in Disk Utility on Mac

Creating a new disk image from a folder is already a menu option from within Disk Utility, making it very easy to use. It’s worth keeping in mind that large folders can take quite a long time to encrypt, so don’t be alarmed. After you’ve encrypted your folders, it’s easy to move these to an external storage device to free up space on your hard drive.

Combine multiple hard disks into a RAID set that acts as a single disk

The final popular use of Disk Utility is a bit more advanced. Using multiple hard disks in a RAID set can increase the performance, reliability, and storage capacity of your data storage system. Many power users prefer to maintain a RAID set to increase performance for multimedia applications like video editing. Implementing a RAID array can boost productivity performance and write speeds for creators when paired with a powerful 15″ laptop. The ability to create and manage RAID arrays recently returned to macOS after being removed in OS X El Capitan.

RAID assistant menu within Disk Utility on MacRAID assistant menu within Disk Utility on Mac

Within Disk Utility you’ll find the option to create and manage four popular RAID versions:

  • RAID 0 (Striped)
  • RAID 1 (Mirrored)
  • RAID 10 (Mirrored set of Striped drives)
  • JBOD (just a bunch of disks)

Each of these configurations has pros and cons, but each is seamlessly managed within Disk Utility by default. Keep in mind that if you attempt a RAID configuration, the most important first step is to back up all of your data! If you are in need of a good external storage option for your Mac, check out our list of best Mac accessories.


Disk Utility is one of the most useful native macOS apps for troubleshooting issues with your hard drive. In addition, you can perform several important backup and encryption tasks from within the application as well. If you’re an advanced user or creator, you may also find the RAID creation and management tool incredibly useful for your workflow. Throughout the life of your Mac you won’t need to repair issues too often, but knowing Disk Utility can help should put your mind at ease.