The first thing to do, assuming you are trying to erase an external disk and not your startup volume, is to use Disk Utility to try and repair it. Once it’s mounted, you’ll be able to erase it. The solution to this one is simple, just choose the disk in Disk Utility’s sidebar and click Mount in the toolbar. If a disk is connected to your Mac but not mounted in the Finder, Disk Utility won’t be able to erase it.

If the disk you’re trying to erase is badly damaged, Disk Utility may not be able to access the information needed to erase it. If you want to erase your startup disk, you’ll need to either boot in Recovery mode or boot from an external USB disk or USB stick.

The disk you’re trying to erase is the disk you booted from.

There are a few reasons why the erase process may have failed on your Mac.

Whatever the reason is, I’ll show you how to deal with it. That could happen because the Disk Utility erase greyed out or unable to complete the task. Occasionally, however, Mac users run into a problem: Disk Utility doesn’t let erase a disk. You can use it to partition, repair, completely erase, or reformat a disk. But to help you do it all by yourself, we’ve gathered our best ideas and solutions below.įeatures described in this article refer to the MacPaw site version of CleanMyMac X.ĭisk Utility is one of the most valuable tools in your Mac’s Utilities folder. So here’s a tip for you: Download CleanMyMac to quickly solve some of the issues mentioned in this article.

Macbook wipe disk