Disk Utilities For Mac

 

Before Mac OS X Panther, the functionality of Disk Utility was spread across two applications: Disk Copy and Disk Utility. Disk Copy was used for creating and mounting disk image files whereas Disk Utility was used for formatting, partitioning, verifying, and repairing file structures. The ability to 'zero' all data (multi-pass formatting) on a. If you’re having problems with a disk, Disk Utility can check the disk and repair problems it detects. How to repair a disk To browse the Disk Utility User Guide, click Table of Contents at the top of the page.

  1. Mac Disk Utility Restore
  2. Disk Utilities For Mac Osx
  3. Disk Repair Utility For Mac

Erasing your disk: For most reasons to erase, including when reformatting a disk or selling, giving away, or trading in your Mac, you should erase your entire disk.

Erasing a volume on your disk: In other cases, such as when your disk contains multiple volumes (or partitions) and you don't want to erase them all, you can erase specific volumes on the disk.

Erasing a disk or volume permanently deletes all of its files. Before continuing, make sure that you have a backup of any files that you want to keep.

How to erase your disk

Disk Utilities For Mac
  1. Start up from macOS Recovery. Then select Disk Utility from the Utilities window and click Continue.
    If you're not erasing the disk your Mac started up from, you don't need to start up from macOS Recovery: just open Disk Utility from the Utilities folder of your Applications folder.
  2. Choose View > Show All Devices from the menu bar in Disk Utility. The sidebar now shows your disks (devices) and any containers and volumes within them. The disk your Mac started up from is at the top of the list. In this example, Apple SSD is the startup disk:
  3. Select the disk that you want to erase. Don't see your disk?
  4. Click Erase, then complete these items:
    • Name: Type the name that you want the disk to have after you erase it.
    • Format: Choose APFS or Mac OS Extended (Journaled). Disk Utility shows a compatible format by default.
    • Scheme: Choose GUID Partition Map.
  5. Click Erase to begin erasing your disk and every container and volume within it. You might be asked to enter your Apple ID. Forgot your Apple ID?
  6. When done, quit Disk Utility.
  7. If you want your Mac to be able to start up from the disk you erased, reinstall macOS on the disk.

How to erase a volume on your disk

  1. Start up from macOS Recovery. Then select Disk Utility from the Utilities window and click Continue.
    If you're not erasing the volume your Mac started up from, you don't need to start up from macOS Recovery: just open Disk Utility from the Utilities folder of your Applications folder.
  2. In the sidebar of Disk Utility, select the volume that you want to erase. The volume your Mac started up from is named Macintosh HD, unless you changed its name. Don't see your volume?
  3. Click Erase, then complete these items:
    • Name: Type the name that you want the volume to have after you erase it.
    • Format: Choose APFS or Mac OS Extended (Journaled). Disk Utility shows a compatible format by default.
  4. If you see an Erase Volume Group button, the volume you selected is part of a volume group. In that case, you should erase the volume group. Otherwise, click Erase to erase just the selected volume. You might be asked to enter your Apple ID. Forgot your Apple ID?
  5. When done, quit Disk Utility.
  6. If you want your Mac to be able to start up from the volume you erased, reinstall macOS on that volume.

Reasons to erase

You can erase at any time, including in circumstances such as these:

  • You want to permanently erase all content from your Mac and restore it to factory settings. This is one of the final steps before selling, giving away, or trading in your Mac.
  • You're changing the format of a disk, such as from a PC format (FAT, ExFAT, or NTFS) to a Mac format (APFS or Mac OS Extended).
  • You received a message that your disk isn't readable by this computer.
  • You're trying to resolve a disk issue that Disk Utility can't repair.
  • The macOS installer doesn't see your disk or can't install on it. For example, the installer might say that your disk isn't formatted correctly, isn't using a GUID partition scheme, contains a newer version of the operating system, or can't be used to start up your computer.
  • The macOS installer says that you may not install to this volume because it is part of an Apple RAID.

About APFS and Mac OS Extended

Disk Utility in macOS High Sierra or later can erase using either the newer APFS (Apple File System) format or the older Mac OS Extended format, and it automatically chooses a compatible format for you.

How to choose between APFS and Mac OS Extended

Disk Utility tries to detect the type of storage and show the appropriate format in the Format menu. If it can't, it chooses Mac OS Extended, which works with all versions of macOS. If you want to change the format, answer these questions:

  • Are you formatting the disk that came built into your Mac?
    If the built-in disk came APFS-formatted, Disk Utility suggests APFS. Don't change it to Mac OS Extended.
  • Are you about to install macOS High Sierra or later for the first time on the disk?
    If you need to erase your disk before installing High Sierra or later for the first time on that disk, choose Mac OS Extended (Journaled). During installation, the macOS installer decides whether to automatically convert to APFS—without erasing your files.
  • Are you preparing a Time Machine backup disk or bootable installer?
    Choose Mac OS Extended (Journaled) for any disk that you plan to use as a Time Machine backup disk or as a bootable installer.
  • Will you be using the disk with another Mac?
    If the other Mac isn't using macOS High Sierra or later, choose Mac OS Extended (Journaled). Earlier versions of macOS don't work with APFS-formatted volumes.

How to identify the format currently in use

If you want to know which format is currently in use, use any of these methods:

  • Select the volume in the Disk Utility sidebar, then check the information shown on the right. For more detail, choose File > Get Info from the Disk Utility menu bar.
  • Open System Information and select Storage in the sidebar. The File System column on the right shows the format of each volume.
  • Select the volume in the Finder, then choose File > Get Info from the menu bar. The Get Info window shows the Format of that volume.

If your disk or volume doesn't appear, or the erase fails

  1. Shut down your Mac, then unplug all nonessential devices from your Mac.
  2. If you're erasing an external drive, make sure that it's connected directly to your Mac using a cable that you know is good. Then turn the drive off and back on.
  3. If your disk or volume still doesn't appear in Disk Utility, or Disk Utility reports that the erase process failed, your disk or Mac might need service. If you need help, please contact Apple Support.

Learn more

  • If you can't start up from macOS Recovery, you can use a different startup disk instead.
  • If Disk Utility shows a Security Options button in the Erase window, you can click that button to choose between a faster (but less secure) erase and a slower (but more secure) erase. Some older versions of Disk Utility offer the option to zero all data instead. These secure-erase options aren't offered or needed for solid-state drives (SSDs) and flash storage.

The Disk Utility on Mac is a very useful system tool for fixing specific disk problems. For example, you can run a disk check when your apps quit simultaneously, an external drive is not working properly, or your Mac won’t startup. Disk Utility will check the health of your hard drive and repair any disk errors if possible.

Disk Utility usually works smoothly, but there are times when frustrating errors occur and prevent the process from being completed. One of the common errors encountered when using Disk Utility is the “Couldn’t Unmount Disk” error. When this error pops up, any attempted task gets stopped right in its tracks.

What is the “Couldn’t Unmount Disk” Error on Mac?

The “Couldn’t Unmount Disk” error can happen during formatting, partitioning, disk verification and repair, or any task that the Disk Utility undertakes. What makes this error frustrating is that there is usually very little to no additional information provided by the error message, making it more challenging to resolve the problem, And based on the error message, it is even harder to determine what the problem is all about.

Here are some variations of the error message that Mac users encounter, depending on the process being executed when the error happened:

  • Disk Erase failed.
    Disk Erase failed with the error:
    Couldn’t Unmount Disk.
  • Partition failed
    Partition failed with the error:
    Couldn’t Unmount Disk.
  • Disk Utility stopped verifying (letter of the hard disk)
    Couldn’t Unmount Disk.
  • Volume Erase failed
    Volume Erase failed with the error:
    “Couldn’t Unmount Disk”.

Once this pops up, the current process gets halted and could no longer proceed, affecting any troubleshooting process or disk repair you might be doing.

What Causes the “Couldn’t Unmount Disk” Error in Disk Utility for Mac?

When your Mac is getting the “Couldn’t Unmount Disk” error when using the Disk Utility, it is possible that the boot drive cannot be modified because it is being used by some process or an application. For example, a file from the disk you are trying to erase could be open, which means that you can’t proceed with the erasing unless all the files are closed.

Another possible reason is the presence of malware. When a malicious software is running in the background and wreaking havoc on your Mac, you might get the “Couldn’t Unmount Disk” error when you try to do something with your hard drive. This is because the malware might be making changes to your hard drive without you knowing it.

Other factors you should look into include corrupted system files, bad hard drive sectors, or insufficient permissions. Whatever the reason is, resolving this “Couldn’t Unmount Disk” error should be your priority because it might lead to further disk damage or other hard drive issues.

How to Fix the “Couldn’t Unmount Disk” Error on Mac

If your Mac is getting the “Couldn’t Unmount Disk” error, don’t worry because there are several ways to handle this problem. But before you do so, here are some of the basic troubleshooting you should take care of first:

  • Close all applications and files before attempting the repair.
  • Make sure you have enough permissions to read and write to the drive you want to modify.
  • Run a scan to check for the presence of malware. Delete any malicious software detected using your antivirus and delete all related files.
  • Disable your security software after running the scan because it might prevent the processes from pushing through.
  • Declutter your system by cleaning up your computer with a Mac cleaning tool. This should fix any errors related to corrupted junk files or cached data on your Mac.
  • Restart your computer.

Once you’ve completed the steps above, you can now proceed with the main solutions:

Solution #1: Use a USB Boot Drive to Repair the Hard Drive.

If “Couldn’t Unmount Disk” error occurs when you are trying to modify the boot drive, the easiest solution is to boot your Mac using another drive, and then run Disk Utility from that disk. You can use an installation drive or a recovery drive, as long as it is bootable and it is separate from the primary boot disk where your macOS is installed.

Here are the steps you need to follow to resolve this error using a USB boot drive:

  1. Connect the USB boot drive to your Mac, then reboot.
  2. While restarting, hold down the Option key button and choose the attached boot drive.
  3. In the boot menu, choose Disk Utility.
  4. Click First Aid at the top menu to verify the disk.
  5. Once your disk has been verified, you can then proceed with the task you were trying to perform when the error occurred.

Solution #2: Use the Recovery Partition.

Utilities

If the “Couldn’t Unmount Disk” error message appears when doing First Aid on your disk or formatting a non-boot disk, the first solution will not work. If this is the case, you can try resolving the error using Recovery Partition.

Mac Disk Utility Restore

Here’s how to do it:

  1. Reboot your Mac.
  2. While booting up, hold down the Option key to boot using the Recovery Partition.
  3. Next, click on Disk Utility from the boot menu.
  4. Click First Aid to verify the disk or select Erase to format the disk if needed.

Disk Utilities For Mac Osx

Keep in mind that this method will only work if the disk that is throwing the error is not the same as the primary boot partition where the Recovery Partition is saved.

Solution #3: Use Command Prompt to Force Unmount the Disk.

If the above methods don’t work and your disk is pretty stubborn, you can attempt to fix this error by forcing to unmount the disk using commands.

To do this, follow the steps below:

  1. Launch Terminal by navigating to Finder > Go > Applications > Utilities.
  2. In the Terminal window, type in the following command: diskutil list
  3. This will list down all the available disks on your Mac.
  4. Look for the disk that you want to force unmount and take note of the number of the drive.
  5. Type in this command next: sudo diskutil unmountDisk force /dev/diskx
  6. Replace /dev/diskx with the disk number of the drive you want to unmount (for example, dev/disk1).
  7. Wait for the process to be completed.

Solution #4: Use a Third-Party App.

Disk Repair Utility For Mac

If you don’t want to go through the trouble of booting using the USB boot drive or typing in commands in the Terminal, you can use a third-party tool instead. There are a lot of repair utilities to help you deal with this “Couldn’t Unmount Disk” error. These utilities can also be used to format, partition, erase, or modify your disk. Just make sure to choose a reliable app that can help you perform these tasks without any error.

Summary

The Disk Utility on macOS is a useful tool for fixing any disk-related issues or performing tasks that involve the hard drive. But this tool is not impregnable. Flaws, such as the “Couldn’t Unmount Disk” error, can happen from time to time. When this happens, simply follow the solutions listed above and you’ll be good to go.

If you’re running into errors and your system is suspiciously slow, your computer needs some maintenance work. Download Outbyte PC Repair for Windows, Outbyte Antivirus for Windows, or Outbyte MacRepair for macOS to resolve common computer performance issues. Fix computer troubles by downloading the compatible tool for your device.
See more information about Outbyte and uninstall instructions. Please review EULA and Privacy Policy.

Recent Posts

  • Iphone Touch Id For Mac
  • The Best Photo Software For Mac
  • Wiki For Mac
  • Medieval Total War For Mac