Disk Repair Utilities For Mac

Mac starts in Recovery Mode. Select Disk Utility & click Continue. Disk Utility app opens up. In the sidebar of Disk Utility, select startup disk (Macintosh HD) that contains macOS Catalina 10.15. Then, click First Aid. If Disk Utility reports the startup disk is about to fail, then you can’t repair the disk. Go to the Apple Menu and click Restart. As your computer restarts, press Command + R when you hear the startup sound. Hold the key combination until the Apple logo appears. Choose Disk Utility when the OS X Utilities pop-up appears. Part 4: Tips for Using Disk Utility and Mac Hard Drive. By now, you would be able to fix the Disk Utility first aid failed issue like a pro. If you don’t want to go through a similar situation again, then consider following these tips.

Repair a storage device in Disk Utility on Mac Disk Utility can fix certain disk problems—for example, multiple apps quit unexpectedly, a file is corrupted, an external device doesn’t work properly, or your computer won’t start up. Disk Utility can’t detect or repair all problems that a disk may have.

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Developed for macOS

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?

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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.

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.

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.

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.

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.

Sep 08, 2020 • Filed to: Answer Hard Drive Problems • Proven solutions

Disk Utility is one of the most resourceful utility tools in Mac that offers tons of features. Whenever there is an issue with Mac’s hard drive, users take the assistance of its “First Aid” feature. Surprisingly, there are times when it doesn’t seem to work and displays the “Disk Utility can’t repair the disk” error instead. While it might seem a bit complicated at first, you can easily fix the Disk Utility first aid failed error in no time. This guide will explain the same in a step by step user-friendly manner.

• Part 1: Why Disk Utility Fails to Repair a Disk
• Part 2: Steps to Fix the “Disk Utility Can’t Repair This Disk” Error
• Part 3: How to Recover Data After Mac Disk Repair
• Part 4: Tips for Using Disk Utility and Mac Hard Drive

Part1: Why Disk Utility Fails to Repair a Disk

Before we get into the details and learn ways to fix Disk Utility can’t repair the disk, let’s quickly know what Disk Utility is all about and the common reasons for this error.

What Is Disk Utility?

Disk Utility is an inbuilt utility application in Mac that helps us manage its internal or external hard drive. Ideally, Disk Utility can help you create or merge partitions, erase a hard drive, unmount it, and even repair it. The “First Aid” option is one of the most widely used features of Disk Utility. It can be used to fix various kinds of issues related to a hard drive without undergoing any data loss.

Main causes of the Disk Utility error

There are times when the Disk Utility first aid feature is failed. Ideally, it can happen due to the following reasons:

• The firmware could be corrupted, leading to the Disk Utility issue.
• Chances are that your hard drive could be damaged beyond the scope of repair.
• You might be running an outdated version of macOS.
• The disk could be removed while performing the first air operation.
• The data in the disk could be corrupted.
• The disk might have a bad sector or could be corrupted by a malware

Part 2: Steps to Fix the “Disk Utility Can’t Repair This Disk” Error

Ideally, it doesn’t take a lot of effort to fix the Disk Utility can’t repair the disk issue. Firstly, you need to back up the existing data on the disk as it might stop functioning anytime. Once it is done, you can reformat the disk or fix the root issue behind it. In the end, you can restore the backup data and start using your Mac the usual way. Here’s a stepwise solution to fix Disk Utility first aid failed issue like a pro.

Step 1: Backup your Disk’s Content

When we get the Disk Utility can’t repair this disk prompt, it is recommended to take a backup of our data first. Mostly, the error depicts that the disk is not stable and can get corrupt anytime. Therefore, if you don’t want to suffer from an unwanted loss of your files, then consider taking a dedicated backup.

To do this, you can use an external hard drive and simply copy-and-paste your files on it. Besides that, you can also take the assistance of a Time Machine for a smoother process.

Disk Repair Utilities For Mac Os

1. Firstly, connect your external drive to your Mac using a working cable. As soon as it gets detected by it, Time Machine will automatically display the following prompt. Just select the “Use as Backup Disk” feature to proceed.

2. In case you don’t get this prompt, then you can manually launch the Time Machine tool from Mac’s System Preferences.

3. Now, just select the backup disk and start the process. Wait for a while as Time Machine would take a dedicated backup of your disk on the external drive. Just make sure that the external drive has enough free storage in advance.

Step 2: Fix the Disk Utility Error

Great! Once you have taken a backup of your important files, you can easily fix the Disk Utility first aid failed error. The following are some of the major solutions to this.

Fix 1: Use the FSCK command

FSCK is an inbuilt command in Mac that can help us manually repair a disk. Though, to run it, you need to first boot your system in a single user mode. Later, you can follow these basic steps to fix Disk Utility can’t repair the disk error.

1. Restart your Mac and hold the Command + S keys for a few seconds while it boots. This will automatically boot it in a single user mode.

2. Once the terminal window of the single user mode is launched, you can just type the command “/sbin/fsck –fy”. This is a disk repair and diagnostic command that will scan the disk and would try to fix it automatically.

3. Since the disk would be read-only in the single-user mode, you need to change that first. To do this, you need to type the command “/sbin/mount -uw /” and press enter.

4. If everything goes well, then you will get the “The volume Macintosh HD appears to be OK' prompt. If not, then enter the “fsck –fy” command a few times till you get this expected message.

5. That’s it! Once the Macintosh HD is fixed, you can enter the “reboot” command to restart your system in the normal mode.

Fix 2: Format the Disk

If the FSCK command is not able to fix the Disk Utility first aid failed problem, then you can also format the disk. Needless to say, this will erase all the existing data from the disk and will also get rid of any malicious entity from it. To do this, you can also take the assistance of Mac’s Disk Utility.

1. Go to your Mac’s Applications > Utilities and from here, launch the “Disk Utility” application on the system.

2. As the Disk Utility window will open, you can view the Macintosh HD and the available partitions (or the external sources). Simply select the disk that you wish to format.

3. Now, click on the “Erase” button on the right and confirm your choice when the following pop-up would appear. You can also select the file format and partition scheme of the disk from here.

4. Click on the “Erase” button again and wait as the disk would be formatted. Later, you can restart your Mac and try to access the disk again.

Step 3: Recover your backup

Once you have fixed the Disk Utility can’t repair the disk issue, you can recover your data. If you have formatted the disk, then all the existing data on it would be lost. The good thing is that you have already maintained a backup of your disk on Time Machine. Now, you can again take its assistance to restore your backup.

1. To begin with, connect your Time Machine disk to Mac and launch the Time Machine application from System Preferences.

2. The Time Machine drive will open for you to browse. Use the arrow keys on the side to browse the backup files.

3. Once you find the data you are looking for, just click on the “Restore” button to save it to its original location.

In case if you have not maintained a prior backup of your data, then you can use a recovery tool. For instance, with the help of Recoverit Data Recovery, you can get back the content from a formatted hard drive. We have explored this solution in the next section.

Part 3: How to Recover Data After Mac Disk Repair

A lot of times, when users get the “Disk Utility can’t repair this disk” error, then simply format the drive without taking its backup. In this case, you can take the assistance of Recoverit Data Recovery. Developed by Wondershare, it is one of the most reliable data recovery tools for Mac. It doesn’t matter what kind of data you have lost and under which scenario, Recoverit will fix it all. This even includes recovering data from a formatted hard drive, corrupt storage, Trash deletion, accidental deletion, and so on.

Step 1: Select a source to scan

Install and launch Wondershare Recoverit Data Recovery on your Mac as soon as you suffer from any unwanted data loss. On the home page of Recoverit, you can see various locations like hard drive, partitions, folders, etc. Just select the formatted hard drive and click on the “Start” button.

Step 2: Scan the source

Sit back and wait for a few minutes for Recoverit to extract all kinds of lost content from the hard drive. It might take a while for the process to be completed. Though, you can pause the process in between if you want to.

Step 3: Restore your data

Once the process is over, all the extracted files will be listed under different categories for you to preview. You can preview the extracted photos, videos, and even documents. Select the files of your choice and click on the “Recover” button to save them.

Part 4: Tips for Using Disk Utility and Mac Hard Drive

By now, you would be able to fix the Disk Utility first aid failed issue like a pro. If you don’t want to go through a similar situation again, then consider following these tips.

• Keep your Mac updated

If your system is running on an old or outdated version of macOS, then it might cause issues like Disk Utility can’t repair the disk. To avoid this, simply go to your Mac’s settings and check for updates. An upgraded system will have fewer chances of encountering these issues.

• Check your hard disk’s health regularly

Most of the Mac users only use the First Aid feature of Disk Utility to fix their hard drives. Ideally, it is recommended to use this feature every once in a while. This will help you diagnose the overall health of the hard drive and you can take preventive measures beforehand.

• Keep enough disk space empty

Mac users often suffer from limited free space on their hard drives. If the disk is packed and does not have enough free space, then it might cause more problems to your system. Therefore, make sure that at least 20% of the hard disk remains empty at any cost.

• Manage partitions efficiently

Disk Utility also makes it easier for us to create, delete, and merge partitions. Ideally, you can keep the firmware and the user data in different partitions to make sure that you can manage your partitions more efficiently.

• Avoid using third-party disk management tools

There are all kinds of third-party tools out there for macOS that works as a substitute to Disk Utility. While they might seem like a more convenient solution, they can cause more harm to your system than good. Carefully pick these third-party tools and only go with a reliable solution.

There you go! Now when you know how to fix the Disk Utility can’t repair this disk issue, you can easily overcome this problem. Since the solution might involve the formatting of the disk, you can consider using a recovery tool like Recoverit. Even if you have not taken a prior backup of your drive, Recoverit would let you get back the lost and formatted content from it. Since it offers a free trial, you can easily give it a shot without spending a single penny.

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