15 Worst Mac Hard Disk Drive Problem with Solutions

This blog summarizes the 15 worst Mac hard drive and SSD data loss problems with recovery solutions. The mentioned storage drive cases in this blog address to USB, Flash storage drive, external hard drive as well. In case your data is lost, or the Mac hard disk drive itself is unrecognized then read more to recover your Mac hard drive with either Time Machine backup or by using a Mac drive recovery software without delay.

While iMacs and MacBook are the most preferred computers, that they’re immune to hard drive issues cannot be said. There are a number of problems that can affect Mac hard drives/SSDs and recovery from them can often be very difficult. We’ve compiled a list of the 15 worst Mac hard drive problems and their solutions. Keep these handy in situations of crisis.

The 15 worst Mac hard drive problems with solution follow:

  1. Mac hard drive not mounting
  2. Slow Mac hard drive
  3. Mac hard disk drive failed SMART status
  4. Mac hard drive’s partition deleted
  5. Mac hard drive clicking noise
  6. Mac hard drive ‘couldn’t unmount disk’ problem
  7. Mac hard drive encryption password lost
  8. Mac hard drive data loss
  9. Disk bad sectors
  10. Unable to partition the disk drive
  11. Mac hard drive ejecting itself
  12. Mac hard drive not detected in Windows
  13. Mac hard drive space disappearing
  14. Mac hard drive cannot be repaired
  15. Mac hard drive not showing up in Disk Utility

1. Mac hard drive not mounting/unrecognized

Problem: When you connect an external hard drive to Mac, it mounts and shows on the desktop. It also appears in Finder. However, sometimes, the disk can fail to mount when you connect it. In such a case it won’t even appear in Finder.

Solution: Some common fixes you can try are:

  • Set your Mac to show all mounted drives on the desktop. Go to Finder -> Preferences -> General -> Tick External Drives
  • Unplug and re-plug the drive
  • Try to connect it with a different cable
  • Use a different USB port to connect it
  • Try connecting it to another Mac

If none of these work, there might be something wrong with your external hard drive. Try to backup your hard drive in question via Disk Utility or a third-party cloning utility so that later, you can erase and reformat the drive with a new file system. However, if there is no backup of your data and you are unable to clone the troubled hard drive then rely on a Mac data recovery software to recover data from unmounting Mac hard drive.

Read Case Study: Whooping 94% data recovered from unmounted external drive on MacBook Pro

2. Slow Mac hard drive

Problem: Age and continuous usage can slow a Mac down. Additionally, a lot of other factors can contribute to degrading Mac performance like hard drive becoming too full, macOS being outdated, crowded startup, too many apps running in the background, hardware issues, etc.

Solution: There are a number of things you can do to give your Mac a performance boost:

  • Delete large unused files, old apps that you no longer use, and duplicate data from the hard drive
  • Clean up the desktop and login items
  • Update your macOS
  • See a list of background processes in Activity Monitor and quit the ones you don’t need
  • Upgrade your Mac hardware and firmware
  • Repair disk permissions

The above list of activities often looks simple, but it actually isn’t. Taking out the time and patience to manually clean up Mac hard drive and perform other tune-up tasks can easily get frustrating. Thus, avoid all hassle and try Stellar SpeedUp Mac. This product automatically removes system junks, large unused files, duplicates, old apps, and unused login items from Mac hard drive with the click of a button.

3. Mac hard disk drive failed SMART status

Problem: Mac hard drive S.M.A.R.T. (also known as Self-Monitoring, Analysis and Reporting Technology) is a monitoring system for internal disks and checks for issues. If the SMART check on your Mac hard disk drive reports errors or failures, it usually means the hard drive is about to permanently fail.

Solution: There still might be hope for your hard drive. In order to cover all recovery chances from your end, follow these steps:

  • Open Disk Utility, select the failing drive and click Repair Disk Permissions
  • If this doesn’t work, start-up with the macOS installation USB/Recovery HD, choose Utilities > Disk Utility, then select the failing drive and click Repair Disk
  • If this also doesn’t work, backup all the files on the disk and then erase it
  • Once the erase completes, run the SMART check again and it should ideally show hard drive status as “Verified”

If none of these steps works, you may need to repair or replace your hard drive with a new one. However, you can leverage Stellar Data Recovery Professional software for Mac to recover the contained files initially and then proceed ahead to replace or repair the affected drive.

4. Mac hard drive’s partition deleted

Problem: While trying to perform partition resizing or reformatting operations, many users report accidentally deleting their partitions having important data. Also, due to issues such as partition table damage, technical issues with the drive, bad sectors, or virus attack, one or more hard drive partitions can get accidentally deleted.

Solution: Use Stellar Data Recovery Professional for Mac software to find the deleted hard drive, partitions or Mac volumes. This application helps locate deleted partitions on any APFS, HFS, HFS+, FAT, NTFS, or ex-FAT based drive. It can quickly redeem deleted volumes on your iMac, Mac Pro, MacBook Pro, MacBook Air, or Mac Mini. Moreover, if the volume(s) on your Mac fails to mount, then this software will help recover the volume data smoothly.

5. Mac hard drive clicking noise

Problem: Mac hard drives typically contain platters on which a magnetic arm reads/writes data. The platters are quite delicate and are easily damaged by the slightest jerk or drop. If you hear clicking noise emanating from your Mac hard drive when you try to boot up your Mac, that could mean your hard drive has suffered physical damage.

Solution: In such a scenario there isn’t much else you can do except:

  • Backup all your important data
  • Run the Apple Hardware Test
  • If you can’t back up your drive, clone it in its present state with Stellar Drive Clone

You’ll probably need to replace your hard drive for a new one or at least get it checked by experts. DO NOT attempt to open it up and mess around since that could further the damage and lead to permanent loss of the data contained in it.

6. Mac hard drive ‘couldn’t unmount disk’ problem

Problem: While trying to repair disk permissions through Disk Utility, you may witness an odd-looking error that says ‘couldn’t unmount disk’. When this happens, you may also be unable to erase or partition the drive. This mainly happens because the boot drive has been modified somehow or it is being used by some other process or application.

Solution: To fix this solution, you’ll need to run “First Aid” on the drive that is throwing this error. This can be done in one of the following ways:

  • Through a bootable USB
  • Through Disk Utility Recovery Partition option

If running First Aid doesn’t fix the error, then you may need to reformat the hard drive with Mac OS X Extended Journaled file system using Stellar Partition Manager. Doing so will recreate a new HFS file structure on the hard drive, which will be free from cryptic errors.

7. Mac hard drive encryption password lost

Problem: Many Mac users use Apple File Vault to encrypt the data on their Mac hard drive. File Vault uses XTS-AES-128 encryption with a 256-bit key to help prevent unauthorized access to the information on your startup disk. However, every encryption works in conjunction with a decryption key which is used to decrypt or unlock the data before it can be accessed. Mostly, this decryption key is a password chosen by you. In the event that you lose or forget your encryption password, you might lose access to your data permanently.

Solution: First make really sure you are typing in the password correctly. Turn off the Caps Lock and choose the Show Password option just to be double sure. If you’re still locked out, try one of these:

  • If the password field shows a question mark, click it to display a password hint which may help you to remember.
  • Try to log in with the Apple ID password that you use for iCloud
  • Reset the password using your Apple ID (this will also reset your keychain, and you will need to again authenticate to access any of the items that were stored in your keychain)
  • Have an administrator reset the login password
  • Use the recovery key you noted when you turned on File Vault disk encryption (for this File Vault must be on)
  • Reset password using the Reset Password assistant (for this File Vault must be on)

If none of the above steps work, contact Apple Support for help!

Related Blog: How to Encrypt, Decrypt, and Recover Deleted Mac Files

8. Mac hard drive data loss

Problem: Data loss from any hard drive is inevitable. There could be any reason for it ranging from technical failure, physical damage, virus/malware attack, system crash, accidental deletion or formatting, drive erasure, etc.

Solution: Recovering all lost data from a hard drive is possible if you take care NOT to overwrite the hard drive from which data has been lost; next, free download DMG of Stellar Data Recovery Professional for Mac software.  

With powerful algorithms allowing the software to scan for recoverable data on your Mac hard drive, this software to recover deleted files from Mac is the best bet you have to recoup all your missing data.

9. Disk bad sectors

Problem: Spotting bad sectors on the hard drive isn’t easy. You might suspect that your Mac hard drive has started developing bad sectors if it throws any nasty errors saying so or if some information suddenly starts to go missing. For example, you save a file normally but on trying to access it later the OS throws out an I/O error because of a bad block it can no longer read.

Solution: There are several fixes to this problem:

  • Run a SMART drive check and fix issues using Disk Utility
  • Clone the drive using Stellar Drive Clone and save the copy on another physical drive
  • Boot to the Recovery partition and run Disk Utility -> First Aid. Repair them and run First Aid again. Keep running it until it says there are no errors.
  • If this doesn’t work, take a full backup of the drive first, then erase it, and finally restore the backup

10. Unable to partition the disk drive

Problem: Performing hard drive partitioning operations is fairly simple using Disk Utility. But in some cases, Disk Utility fails to create partitions on Mac hard drive or perform other related partitioning operations.

Solution: Try macOS Sierra partition manager software Stellar Partition Manager for all your hard drive partitioning needs on Mac. This software works with all OS X versions up to Sierra and helps you perform tasks like creating partitions, deleting partitions, formatting partitions, resizing partitions, hiding/revealing partitions, etc.

11. Mac hard drive ejecting itself

Problem: Some of you may have tried replacing your Mac CD/DVD drive with a large capacity hard drive. Doing this augmented your Mac’s storage capacity, but also brought forth auto hard drive ejection issue after a few minutes of drive idleness.

Solution: To resolve the eject issue, you need to tweak the power management settings of your Mac, as shown here:

  • Go to Finder > Applications > Utilities > Terminal.
  • On Terminal, type “pmset –g | grep disksleep” and hit Return.
  • Check the value of disksleep. If it is low, you need to provide a significant number.
  • Type “sudo pmset –a disksleep #” (replace # with a suitable number) and hit Return.
  • Provide admin password when prompted.
  • Check the changed sleep value by using “pmset –g | grep disksleep” command.

The above solution will fix the drive auto-eject problem. Now, you can use the hard drive to save and access data usually.

12. Mac hard drive not detected in Windows

Problem: When you connect a Mac-based storage drive on a Windows PC, it won’t appear on File Explorer. This issue arises due to the incompatibility of file systems. Your storage drive may in APFS or HFS+ file system format that is compatible exclusively to macOS. No other operating system is harmonious to the proprietary file system format of Apple.

Solution: To fix the issue, do the following:

  • Back up all the data from the storage drive from its compatible operating system.
  • Format the drive in the ex-FAT file system. (You can even format your USB flash drive in FAT32, but it will only allow storing of files with a size limit of 4 GB.)
  • Restore the backed up data to the storage drive.

Now, you can use the storage drive in both Mac as well as Windows computer. Windows can read-write on ex-FAT as well as FAT32 file system formatted storage drive.

Related Blog: How to Recover Data from Mac Hard Drive on Windows

13. Mac hard drive space disappearing

Problem: Low free space is a concern for Mac users if they are using a low capacity storage drives (say 128 GB SSD). “Your startup disk is almost full” is a norm for such users. Even if you keep your essential data in iCloud and large multimedia files in an external storage drive, your Mac storage drive free space will disappear automatically. This happens due to the buildup of junk files, temporary files, caches, logs, and leftovers of application.

Solution: To resolve the drive space disappearing issue, you need to make more space available on your startup disk by deleting temporary files:

  • To remove caches:
    • Open Finder from Dock.
    • From the Menu Bar, click on Go, then click Home.
    • Click the cog icon from the top pane and select “Show View Options.”
    • On the popup window, select the “Show Library Folder” checkbox, then close it.
    • Go to Library > Caches.
    • Delete all the caches.

Alternatively, you can do the following:

  • Open Finder from Dock.
    • From the Menu Bar, click on Go, then click “Go to Folder.”
    • From the dialog window, type ~/Library/Caches then click Go.
    • Delete all the caches.

You can delete all the temporary files from specific folders present in the Library folder, such as Logs, unneeded iTunes files, and Application Support files. This frequent temporary file removal will increase free space on your Mac and prevent drive disappearing issue. Alternatively, you can use Stellar SpeedUp Mac utility to perform the task readily.

14. Mac hard drive cannot be repaired

Problem: By using the First Aid tab present in Disk Utility, you can fix your hard disk drive or other storage drives for errors, bad sectors, etc. But this is not always the case. Sometimes, you’ll encounter the message “Disk Utility can’t repair this disk.” This error happens because Disk Utility fails to repair your storage drive.

Solution: Use the “file system consistency check” (fsck) command from Terminal in Single User Mode to review and repair the basic structure of your storage drive. But, first off, back up the drive to another external storage medium to ensure you don’t lose data due to troubleshooting error. Next, perform the following steps:

  • Start or restart you Mac then immediately press-hold Command + S keys until white text appears on the startup screen. Your Mac will boot into Single User Mode.
  • On the Terminal, type “fsck –fy” and hit Return. Don’t interrupt till the command finishes, as it can incur data loss.
  • When you see the message “The volume was modified” or “The volume Macintosh HD could not be repaired,” use the above command again.
  • Use the command multiple times until you get the message “The volume Macintosh HD appears to be OK.” Type exit to restart your Mac.

15. Mac hard drive not showing up in Disk Utility

Problem: The Mac storage drive fails to show up in the Disk Utility window.

Solution: Mac hard drives not appearing in the Disk Utility window is one of the worst problems that a device could face. In most cases, the device is either dead wholly or partially. As far as an unmounted Mac hard drive is concerned; the drive still appears in the Disk Utility window though the drive seems to be greyed-out. Fortunately, a Mac hard drive recovery software rescues the stored files from the unmounted media, and later the drive can be erased for reuse.

In case of a dead Mac hard drive, it is advisable to replace the drive after data recovery is performed via a data recovery service provider.


There you go! In this post, we outlined the most challenging problems your Mac hard drive, Solid-State Drive, or other storage drives and partitions can come across. But if you implement the solutions mentioned in this post, you can avoid data loss. But keep in mind, critical troubleshooting steps must be performed after taking a full backup of the storage medium.

In case you lose data during or after performing the troubleshooting steps due to inadvertent error or otherwise, don’t lose hope. Instead, try the trustworthy software Stellar Data Recovery Professional for Mac to get back your lost data. The software is quite intuitive and recovers lost data in 3 key steps: Select, Scan, and Recover.

Also, to fix issues of cloning, Stellar Drive Clone is quite handy, to auto-remove system junks Stellar SpeedUp Mac is useful, and to manage partition Stellar Partition Manager can be your savior. Stellar’s award-winning utilities are always there to help overcome the issues of Mac, effortlessly.


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