How to fix Macintosh HD not mounted in High Sierra/Disk Utility?

Posted by Katrina to Mac Data Recovery on May 3th, 2018

Unable to mount Macintosh HD in Disk Utility on macOS High Sierra and access the data stored on the Mac hard drive? Don't worry. This article will show you how to fix Macintosh HD not mounted on High Sierra Disk Utility issue without losing data.

Macintosh HD not mounted problem is quite common in macOS High Sierra, Mojave and any other Apple operating system. Once the Macintosh HD won't mount in Disk Utility, all the data on the Mac hard drive becomes inaccessible, and most of the operations are greyed out or disabled except the Erase button. But erasing process will wipe all the data stored on the Macintosh HD.

So, what can you do when Macintosh HD is unmountable in Disk Utility High Sierra without worrying about data loss? Read on to learn:

Part I: Why does Macintosh HD not mounted in High Sierra Disk Utility?

If Macintosh HD can't be mounted in Disk Utility, it's mainly because that the file system of the drive is corrupted and the operating system can't recognize it. In general, the corruption is due to incorrect formatting of the disk, power failure, partition table damage, virus attacks, disk corruption and others.

Part II: How to recover data when Macintosh HD not mounted in High Sierra Disk Utility?

Pro tips: Before fixing the Macintosh HD not mounted in High Sierra Disk Utility issue, please stop using the Mac computer and make sure you have a backup copy of the Mac hard drive.

That's because, your any further operation on the Mac computer, including troubleshooting the Macintosh HD errors, may write new data to the unmounted Mac hard drive and overwrite the original data. Without backups, you need to recover data from the not mounted Mac hard drive with iBoysoft Mac Data Recovery.

iBoysoft Mac Data Recovery is free Mac hard drive data recovery software which helps you recover data from the unmountable Macintosh HD, recover data from formatted drives, recover data from unreadable drives, and recover data from corrupted drives, etc. It is fully compatible with macOS Mojave 10.14/High Sierra 10.13/10.12 and OS X 10.11/10.10/10.9/10.8/10.7. It supports documents, pictures, audios, videos, emails, etc. and different storage devices such as hard drives, external hard drives, USB flash drives, SD cards, etc.

Method 1: If you have only one Mac computer

If you have only one Mac computer, please directly run iBoysoft Mac Data Recovery bootable media from iBoysoft Server and recover lost data from the unmountable Macintosh HD.

Method 2: If you have two Mac computers

Step 1: Download iBoysoft Mac Data Recovery on the healthy Mac computer.

Step 2: Install and launch iBoysoft Mac Data Recovery on this Mac computer.

Step 3: Click iBoysoft Data Recovery on the menu bar and then select "Create Boot Drive".

iBoysoft Data Recovery create bootable drive

Step 4: Insert a USB drive into this healthy Mac computer.

iBoysoft Data Recovery create bootable drive

Step 5: Follow the wizard to create a bootable recovery drive on the USB drive.

iBoysoft Data Recovery create bootable drive

iBoysoft Data Recovery create bootable drive

Step 6: When the creation process completes, you can insert the USB drive into the unbootable Mac computer, and then press the Power button and Option key (⌥) to start the Mac up.

iBoysoft Data Recovery create bootable drive

Step 7: Select iBoysoft Mac Data Recovery from the boot options.

Step 8: Follow the wizard to scan for the lost data on the unmounted Macintosh HD.

Step 9: Choose the files you want to get back, and then click Recover button.

Part III: How to fix Macintosh HD not mounted in High Sierra Disk Utility?

After recovering data from the Mac hard drive that is not mounted in Disk Utility High Sierra, you can follow the solutions to fix the issue.

Solution 1: Repair the unmountable Macintosh HD in Recovery Mode

If the Macintosh HD is unable to be mounted in Disk Utility normally, you can try to fix it with Disk Utility's First Aid in Recovery Mode.

Step 1: Boot your Mac into Recovery Mode. Start your Mac and hold down the Command and R keys simultaneously until you see an Apple logo or spinning globe. Then release the keys.

Step 2: Select Disk Utility from the macOS Utilities menu and click Continue.

Step 3: Select the unmountable Macintosh HD from the left-hand panel.

Step 4: Click First Aid on the top of the window and wait while it verifying and repairing errors.

Repair unmountable Macintosh HD via First Aid

Solution 2: Fix Macintosh HD not mounted issue with Terminal

If Disk Utility stopped repairing Macintosh HD in High Sierra, you can then try to fix it with Terminal.

Step 1: Boot your Mac into Recovery Mode.

Step 2: Click Utilities from the menu bar and select Terminal from the drop-down list.

Step 2: Enter diskutil list. This will list out the available volumes.

Step 3: Check the volume identifier from the table that appears. (For example disk 2s)

Step 4: Enter diskutil repairVolume/disk 2s. (Replace disk 2s with the volume identifier of your Macintosh HD)

Solution 3: Run FSCK command in Single User Mode

FSCK is a command-line tool to check the consistency of a hard drive and repair disk errors. If the solutions above are unable to fix Macintosh HD/Mac internal hard drive not mounted issue, you can have a try.

Step 1: Restart your Mac and, before the Apple logo appears, hold down Command and S keys. This will boot your Mac into Single User Mode.

Step 2: Type in: /sbin/fsck -fy.

Step 3: If you see "File system was modified", then re-type in the command again until you see "The volume [name] appears to be OK".

Use FSCK command in Single User Mode

Step 4: Type in reboot to restart your Mac.

Solution 4: Try Safe Mode

When trying to boot into Safe Mode, macOS will scan and repair any errors it finds on the disk. To boot into Safe Mode, you need to shut the Mac down and start it up while holding down Shift. Release the Shift key when you see the login window. Should your computer boot properly, try restarting and booting as normal.

Solution 5: Erase the unmountable Macintosh HD and reinstall macOS

If you failed to repair the unmountable Macintosh HD through the solutions above, the final chance is to reformat it. But as you know, reformatting will erase all the data stored on the Macintosh HD. Please make sure you have recovered data with iBoysoft Mac Data Recovery as above.

Step 1: Boot your Mac to Recovery Mode.

Step 2: Select Disk Utility from the macOS Utilities menu.

Step 3: Select the unmountable Macintosh HD from the side bar.

Step 4: Click Erase from the top.

Step 5: Setup the required information (i.e. Name, Scheme, Format, etc.) to reformat the disk and click Done when finished.

Step 6: Go back to macOS Utilities screen and select Reinstall macOS.

What to keep in mind: Once you encountered the Macintosh HD not mounted in Mojave/High Sierra/Disk Utility error, the first thing you should do is to save your data on the Mac hard drive. Without regular backups, a data recovery program like iBoysoft Mac Data Recovery will help you recover data from the unmounted Mac hard drive. Then, try to fix the Macintosh HD not mounted issue.

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