How to Format a Mac Hard Drive With Disk Utility

For systems using OS X El Capitan and later macOS versions

Disk Utility is a free application that comes with Mac computers. It's a multi-purpose tool that handles formatting, erasing, repairing, and partitioning hard drives, among other things. If you're preparing a Mac for resale or troubleshooting a misbehaving machine, you might opt to format your Mac's hard drive. Here's a look at how to use Disk Utility to perform this function.

The information in this article applies to Disk Utility on systems with macOS Catalina, Mojave, High Sierra, and Sierra, as well as OS X El Capitan. In OS X Yosemite and earlier versions, Disk Utility had a different interface.

How to Format a Hard Drive for Mac

When you format a disk with Disk Utility, it can be your Mac's main hard drive, which is referred to as your startup disk, or any other drive, including a USB flash drive, SSD, or another storage device. The formatting process erases and formats the selected drive.

In this example, we'll look at formatting a Mac's startup disk. Note that the instructions are slightly different if you're using macOS Catalina.

The process of formatting a disk will erase all data currently stored on the device. Make sure you have a current backup if you intend to keep any data already present on the drive.

Format Your Hard Drive With Disk Utility and macOS Catalina

We'll first look at this process in Catalina. There's an extra step because this macOS adds a second data volume.

  1. Start your Mac from macOS Recovery.

    To do this, restart your Mac and immediately press and hold Command + R. When you see a startup screen, such as an Apple logo or spinning globe, release the keys. Enter a password if prompted. When you see the Utilities window, startup is complete.

  2. Select Disk Utility from the Utilities window in macOS Recovery, and then select Continue.

    Screenshot of Disk Utility under macOS Utilities
  3. In the sidebar, locate a data volume with the same name as your hard drive, for example, Macintosh HD - Data. If you have this volume, select it.

  4. Select Edit > Delete APFS Volume from the menu bar, or select the delete volume button ( ) in the Disk Utility toolbar.

  5. When prompted to confirm, select Delete. (Don't select Delete Volume Group.)

    deleting Mac hard drive in Catalina
  6. After deleting the volume, select Macintosh HD (or whatever you named your drive) in the sidebar.

  7. Select the Erase button or tab.

  8. Enter a name that you want the volume to have after you erase it, such as Macintosh HD.

  9. Under Format, choose either APFS or Mac OS Extended (Journaled) to format as a Mac volume. Disk Utility shows the recommended Mac format by default.

  10. Select Erase to begin erasing the disk. You may be prompted to enter your Apple ID.

  11. When done, quit Disk Utility to return to the Utilities window.

  12. If you want your Mac to be able to start up from this volume again, choose Reinstall macOS from the Utilities window, then follow the onscreen instructions to reinstall macOS on the volume.

Format Your Hard Drive With Other macOS Versions

If you're using Mojave, High Sierra, Sierra, or OS X El Capitan, there's no additional volume to delete.

  1. Start your Mac from macOS Recovery.

    To do this, restart your Mac and immediately press and hold Command + R. When you see a startup screen, such as an Apple logo or spinning globe, release the keys. Enter a password if prompted. When you see the Utilities window, startup is complete.

  2. Select Disk Utility from the Utilities window in macOS Recovery.

  3. Select Continue.

  4. Select your main hard drive in the sidebar on the left. It's typically called Macintosh HD unless you changed the name.

    Disk Utility OS X El Capitan
  5. Select the Erase button.

  6. Under Format, choose either APFS or Mac OS Extended (Journaled) to format as a Mac volume. Disk Utility shows the recommended Mac format by default.

    erasing mac hard drive
  7. Press Erase to begin erasing the disk. You may be prompted to enter your Apple ID.

  8. When done, quit Disk Utility to return to the Utilities window. 

  9. If you want your Mac to be able to start up from this volume again, choose Reinstall macOS from the Utilities window, then follow the onscreen instructions to reinstall macOS on the volume.