7 feasible solutions to fix Macintosh HD not mounted/showing in High Sierra/Disk Utility

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

Summary: Unable to mount Macintosh HD in Disk Utility on macOS High Sierra/Mojave or access the data stored on the Mac hard drive? Don't worry. This article will show you 7 efficient solutions fix Macintosh HD not mounted/showing on High Sierra/Mojave or in Disk Utility issue without losing data.

Mounting a drive means to make the drive available for the operating system to perform read and write operations. If 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. What's worse, your Mac computer will stop working.

While Macintosh HD not mounted problem is quite common in macOS High Sierra, Mojave and any other Apple operating system. A Mac user are asking for help in Reddit:

Help, my 2011 iMac just randomly stopped working this morning. I turned it on, it took about 3 minutes to get to halfway then it shuts off. I used Disk Recovery. When I got there, Macintosh HD was grayed out and every time I tried to repair it, it says "cannot repair" and says to backup the files and stuff, but I don't know how to. Would I need to erase my Macintosh HD or is it possible to recover files from an unmounted, unrepairable drive?

Do this sound familiar? If you have met the situation above, what can you do when Mac hard drive is not mounted in Disk Utility High Sierra/Mojave without worrying about data loss? Read on to learn:

Part I: Why does Macintosh HD not mount in High Sierra Disk Utility?
Part II: How to recover data when Macintosh HD not mounted in High Sierra Disk Utility?
Part III: How to fix Macintosh HD not mounted in High Sierra Disk Utility issue?

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

In the followings, we will unveil its 5 primary reasons why this might happen:

  • > File system damage. File system is responsible controlling how data is organized and stored in a drive. If the Macintosh HD's file system is corrupted, the master file table will be impacted in a direct manner and Mac won't mount the drive.
  • > Virus attack. Perhaps, your Mac system or the Macintosh HD is attacked by virus or malware, resulting in data corruption. Then your Mac won't mount the Macintosh HD.
  • > Catalog file corruption. Catalog files contains the record files of partitioned volumes. So if any catalog file becomes corrupt, the Mac won't be able to get volume size location, description of volume content and other volume information, let alone mount the drive.
  • > Disk Utility failures The Macintosh HD not mounted issue may be caused due to Disk Utility faults.
  • > System malfunctions. System malfunctions include machine malfunctions and operating system errors. If the Mac operating system crashes, it cannot mount any drive.

Part II: How to recover data when Macintosh HD not mounted/showing 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 hard drive not mounting 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 or use Target Disk Mode.

Method 1: Recover data from unmountable Macintosh HD 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.

Featuring a delightful simple interface, iBoysoft Mac Data Recovery make file recovery very easy by having simple interface. Within three steps - select, scan and recover, you can get all lost data back. Moreover, it also provide with powerful preview features and different filtering functions. After scanning, it allows you to preview all recoverable files no matter what file types you have lost, including documents, photos, videos, music files, emails, etc. The filtering and sorting functions enable you to quickly target the right content from a mass of scanning results.

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.

If you have two Mac computers

If you can find another Mac computer, you can take out the Macintosh HD and plug it in the healthy computer as an external one. Download, install and run iBoysoft Mac Data Recovery on the healthy computer and perform data recovery.

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: Select the USB drive to create boot drive, and click "Make bootable". Then iBoysoft Mac Data Recovery will starting to create bootable recovery 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.

Method 2: Use Target Disk Mode

Target disk mode is a boot mode which allows you to browse and transfer files to and from a Mac internal hard drive without booting macOS. It can be used for troubleshooting the internal hard drive not showing up on Mac.

Step 1: Please find another Mac and then connect both Macs with a firewire.

Step 2: Start Mac with failed internal dive and press "T" key button. Then this Mac will enter the Firewire mode, in which there is a Firewire icon on the screen. Meanwhile, you will see the malfunctioning Mac drive on the well Mac.

Use Target Disk Mode on Mac

Step 3: Now you can repair the disk and extract the data from the failed drive on this healthy Mac.

Part III: How to fix Macintosh HD not mounted/showing 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: Restart your Mac computer

No matter what happens to your Mac computer, the first and foremost solution is to shut down your Mac computer and start it up again. Simply holding down the on/off key until the computer turns off, waiting a few minutes, and then turning it back on. Sometimes when you turn it back on, everything returns to normal.

Solution 2: 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 3: Fix Macintosh HD not mounted by 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 4: 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 5: 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 6: Reset NVRAM on your Mac

NVRAM is a small amount of memory used to store certain settings for quick access on Mac. The corrupted NVRAM can cause Mac glitches or even prevent macOS from starting. Thereby if your Mac computer won't boot properly, you can attempt to reset the NVRAM. Reboot your Mac and hold down the "Command + Option + P + R" key buttons. After resetting, you can retry to mount the Macintosh HD on Mac.

Solution 7: 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.

Final thoughts

It's so frustrating that Macintosh HD won't mounted in High Sierra/Mojave Disk Utility, especially when you have important data stored on the drive. But the good news is that quite a few feasible solutions are available to fix this issue. Before that, if you care about data on the Macintosh HD, you should recover data from the unmountable Macintosh HD with iBoysoft Mac Data Recovery. Download and install this free Mac data recovery software, you won't be bothered by any data loss scenarios.

Which solution helps you the most? Do you have any other solutions to fix Macintosh HD not mounted issue or have any question? Please don't hesitate to email us.

Still have questions?