Can't erase or reformat a drive in macOS Disk Utility? 3 easy ways to repair (2024)

Door And Helier 24 comments Last updatedJanuary 29, 2020

You cannot reformat a drive in macOS Disk Utility if the Erase button is grayed out. This can happen for several reasons, all of which prevent you from erasing or reformatting the drives connected to your Mac.

If you are unable to erase disks using your MacBook's Disk Utility, follow the steps below to resolve the issue.

Related:

• Mac or MacBook not recognizing external drives, troubleshooting tips
• My Mac's startup disk is almost full, but I can't delete anything
• Restore MacBook Air and other Macs running macOS to factory settings
• How to Format an SD Card on Your Mac

Erase or reformat a drive with Disk Utility

Let's start with a brief explanation of the correct way to reformat or erase drives with your Mac. Feel free to skip this section if you already know how to do this.

You may want to erase your drive to quickly make room for new files. Or you may need to reformat it to work with different operating systems such as Windows, Linux,or even iPadOS.

When you reformat a drive, all data on it is also erased. So make sure you backup all important files before erasing or reformatting your drives.

Once done, here's how to erase or reformat drives:

1. OpenDisk Utilityfrom the Utilities folder in your programs.

   

2. From the sidebar, select the drive you want to erase or reformat.
3. click onTo deletebutton at the top of the window.

   

4. Choose a new name and format for your drive, then clickTo delete.

   

5. Wait for Disk Utility to erase or reformat your drive, then clickfinished.

   

What should I do if the Erase button in Disk Utility is grayed out?

You're probably reading this article because the Erase button was grayed out when you tried to erase or reformat a drive with Disk Utility. Use the steps below to resolve the issue and let us know in the comments which one worked for you.

Step 1. Show all devices and remove the parent drive

By default, Disk Utility only shows the volumes on your connected drives rather than the drives themselves. A volume is the partition or section of a disk where you store data.

OpenDisk Utilityand selectView > Show all devicesfrom the menu bar. The device names for each of your drives should appear in the sidebar.

Select the parent folder of the drive you want to reformat or delete, then clickTo deletebutton again. Please note that when you delete a device, all volumes within it are also deleted.

Step 2. Run First Aid to repair your drive before erasing it

Disk Utility has a First Aid feature that fixes all kinds of problems with your drives: slow performance, corrupt files, or unexpected behavior. When you run First Aid, it scans the entire drive for errors and tells you if there are any errors that it can't fix.

OpenDisk Utilityand select the drive you want to erase from the sidebar. Click at the top of the windowE.H.B.O.button and then acceptraceE.H.B.O.

How long it takes to perform First Aid depends on the size of your drive, how much data is on it, and how many errors need to be fixed.

Combine this step with the previous one to perform First Aid on the parent device for your drive, as well as on the individual volumes.

Step 3. Boot into recovery mode to erase your startup drive

If you want to reformat or erase your Mac's startup disk, you'll first need to boot into recovery mode. The startup disk is your computer's main hard drive—the one that stores macOS and all your data. It's usually not possible to erase the startup disk because your Mac uses it to run macOS.

Recovery mode is a special partition on your Mac that you can use to restore from a backup, reinstall macOS, get online support, or wipe your startup disk.

You shouldbackup your Macbefore attempting to delete or reformat it.

When you're ready to boot into recovery mode, restart your Mac and hold downCmd + Rwhile it boots up. Continue holding both keys until you see an Apple logo or hear a startup sound.

You should see onemacOS Utilitieswindow appears. to electDisk Utilityfrom this window and try erasing or reformatting your drive again.

Learn how to reinstall macOS after wiping your drive

After you erase or reformat the startup disk (if that was your goal), you'll need to reinstall macOS before you can use your Mac again. This is because the original macOS installation was on the startup disk you just removed.

Reboot into recovery mode to reinstall macOS or follow our guidereset any Mac to factory settings. When you reinstall macOS, your Mac behaves as if it were a brand new machine, with no data on it, waiting for you to set it up.