Hard Drive Not Mounting On Mac

It can check and repair file system errors on Macintosh HD, external hard drive, USB flash drive, SD memory card, etc. Steps to fix external hard drive not mounting issue with First Aid. Most of the time, when you connect an external hard drive to your Mac’s USB port, you soon see it mount on the desktop. The reasons for an external hard drive not mounting on macOS Catalina can be various. The common ones include— storage device connectivity issue, incompatible file system, corrupt file system, and incompatible driver software of the storage drive. In this blog post, we shared various solutions to troubleshoot the problem. Once done, close Disk Utility, safely eject the external hard drive and reconnect to Mac. Then, the disk is mounting properly on Mac. External Hard Drive Not Mounting on Mac Is Fixable, Go and Make It Work Now. When an external hard drive or internal hard drive is not mounting on Mac, it won't be showing up. In this video i am explaining how to fix the not mounting external hard drive problem on macif you found it helpful https://buymeacoffee.com/ino0r. Nov 12, 2021 If an external hard drive is mounted to a file format that is not acceptable by MacOS like NTFS, it can't mount an external hard drive on Mac. Here the only option is to convert an external hard drive file format to Mac compatible ones like HFS+, exFAT, etc.

macOS alerts you when an externally connected drive was unmounted before the operating system had a chance to tidy up all the loose ends on it. In some cases, you may be unable to remount a drive ejected early due to a power outage, shutting a computer down abruptly, or pulling a plug before macOS was ready.

A few Terminal commands can help in at some cases, including solving a problem for one Macworld reader who had amassed three drives that could be mounted under Windows but macOS refused mount or allow Disk Utility to perform repairs on. (This problem may affect drives formatted for Windows and macOS mounting more than HFS+ or APFS formatted drives, but it’s unclear.)

First, you need to find out what macOS’s internal representation of the disk is:

  1. Plug the drive in and power it up if necessary.

  2. Launch Terminal.

  3. Type the following and press Return:

    diskutil list

  4. In the resulting list, find the disk number associated with the unmounted volume. You may see multiple entries that start the same (as in the figure), such as disk3, disk3s1, and so forth. The first part is all that’s needed.

  5. Type the following and press return:

    diskutil eject diskX

    (replace diskX with the number of the disk, like disk3).

  6. Power down the drive if it has a power switch. Disconnect it from the Mac in all cases.

  7. Reconnect the drive and power it up if necessary. It should now appear on the desktop.

The Macworld reader who reported this problem and that the solution worked for some drives had to use an additional bit of troubleshooting to fix another. A background process called QuickLookSatellite, which manages some aspects of generating previews for QuickLook in the Finder and elsewhere, had stalled. You can force quit that process via Activity Monitor:

  1. Launch Applications > Utilities > Activity Monitor.

  2. In the find field in its upper-right corner, enter QuickLookSatellite.

  3. Select each match that appears and click the X (Force Quit) button in the top-level corner, and confirm by clicking the Force Quit text button.

QuickLook will automatically restart any processes it needs, so there’s no need to launch the background process by itself.

This Mac 911 article is in response to a question submitted by Macworld reader Fiona.

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We’ve compiled a list of the questions we get asked most frequently along with answers and links to columns: read our super FAQ to see if your question is covered. If not, we’re always looking for new problems to solve! Email yours to [email protected] including screen captures as appropriate, and whether you want your full name used. Not every question will be answered, we don’t reply to email, and we cannot provide direct troubleshooting advice.

If it doesn't, follow these steps: Step 1 Look for Your External Hard Drive in 'Finder' Interface. First of all, click on File, and then press the New Finder window. Now, look for the hard drive below the Remote Disk. Step 2 Make Sure the External Hard Drive Is Properly Connected to Mac. If an external hard drive is mounted to a file format that is not acceptable by MacOS like NTFS, it can't mount an external hard drive on Mac. Here the only option is to convert an external hard drive file format to Mac compatible ones like HFS+, exFAT, etc. In this Video, I share what I had to do to fix my external hard drive to mount properly. If your hard drive is not being able to read and has errors, this co. My WD 250gig hard drive was accidentally unplugged while I was uploading pictures onto it. Now i'm unable to mount it. I have a Macbook Pro 2.16 GHz Intel Core Duo 1GB 667 MHz RAM I ran disk utility on startup, and it is detected, but I am unable to repair it. If your external hard drive appears there but is not mounted, you can click the Mount icon then the external hard drive will be mounted in macOS Catalina/Mojave. However, if the external hard drive appears in Disk Utility but is unmountable or no volumes of that external drive listed, you got both good news and bad news.

Summary: This post introduces 5 solutions you can try when you are unable to mount an external hard drive on your Mac. Also, to avoid further data loss, you can use iBoysoft Data Recovery for Mac to recover lost data from this unmountable external drive first.

Table of contents
1. Why you can't mount your external hard drive on Mac?
2. How to fix when external disks won't mount on Mac?
3. Conclusion

After you connect an external hard drive to your Mac, if everything is working fine, the operating system will automatically recognize, read, and mount your external drive, as well as show it in the Finder and on the desktop. However, if your disk gives up the ghost just like the users below, the external disk will not be showing up as normal. And if you check it in the Disk Utility, you will find your drive unmounted there.

'I was able to use my 3 TB external hard disk drive to backup my data last week. But now it doesn't mount after I migrate from Mojave to macOS Catalina. I dug around and tried a lot of stuff but still can't mount this external hard drive on my Mac. Can someone explain how to get this drive mounted so I don't lose the data?'

So let’s say you start having trouble with your internal drive, and want to troubleshoot it. Or maybe you want to use your portable macOS installation on another compatible Mac. To boot from your external Sierra drive, plug it into the Mac in question, press the power button, and hold the “Option key until the recovery disk screen appears. Jan 06, 2006 Under OS X by default, external drives are only mounted when a user logs into the system on the console. Other systems such as linux and Solaris typically mount drives during system boot. This means that if you ssh into OS X then your external drives.

Why an external drive is not mounting on Mac?

There are numerous reasons for the external hard drive not mounting issue. The following are a few of the most common ones:

Hardware and connectivity issue

Most of the time, you can't mount your external drive on a Mac just because the connectivity is not in proper condition. This issue may be affected by a loose fitting, a broken USB cable, the wear on USB ports, etc. Sometimes, such connectivity issues could make your external drives keep disconnecting, or much worse, it would make your external hard drive unmountable eventually. After all, it is essential to have a firm and tight connection.

Corrupted disk

Another possible reason for an unmounted disk may come from the problematic hard drive itself. Wonder how could it be? Well, it is possible that you're unable to mount a drive just because it is corrupted and unrecognizable by macOS. You can recall if your external drive has experienced one of these things: an unsafe removal when you are transferring files, an improper ejection, a sudden power outage, or even a virus infection. If so, your disk might be corrupted and it should be the culprit that you are unable to mount your external drive probably.

Incorrect formatting of the disk

In some cases, an unsupported file system will make your external drive unmountable. It is reasonable because if your Mac can't even read your disk's file system, how can you mount and access this hard drive on your Mac? This factor may not be as possible as the other causes, but it does happen.

Unable to mount external hard drives on Mac, how to fix?

Even though the reasons for a not mounting disk are different from case to case, certainly there are some things you can do to fix this issue. The following are five effective solutions to the 'external hard drives won't mount on Mac' issue, and some of them are just basic checks.

Solution 1: Check and fix connectivity issues

The first thing you can do is to make sure that your disk is connected to your Mac properly. Here are some things you can try.

  • Reconnect your external hard drive to your Mac and ensure that it fits the USB port snugly.
  • Connect the external hard drive to a different USB port or a different Mac. If you are not sure if there is a problem with the USB port/hub, you can plug a working external drive in to a port/on a hub, unmount and eject it. Then plug the unmountable external hard drive into that port/hub.
  • Replace the USB cable or adapter in case that it was damaged or broken.
  • Connect it to a Windows PC and see if the storage device is powered on and working.

Solution 2: Check the file system of the external hard drive

Well, if you don't know exactly what file system your disk is formatted with while your external hard drive can't be mounted now, you can go to Disk Utility to have a check if it is formatted with an unsupported file system. Remember that macOS is friendly with APFS and HFS+ and is in a neutral attitude with FAT, FAT32, and exFAT. However, it is a different story if you need to access and write to NTFS file system on Mac. By default, macOS only enables NTFS drive read support but disables write support. In this case, you can download a free NTFS driver for macOS to mount this external hard drive in read and write mode.

Still unable to mount the external hard drive on Mac? Then it should be some problems with the drive itself. You can try the following solutions to troubleshoot this problem.

Wait! Have you recovered your important data from this unmountable drive?

Before you go any further to fix this unmountable hard drive, you'd better make sure you have backed up your data on this drive to avoid data loss. The reason is that when your external drive won't mount, you lose the only access to all your files on this drive. In this situation, if you have important files on the external hard drive, any operations on the drive could overwrite the original data and cause irreparable data loss.

External Hard Drive Not Mounting On Mac

Forget to back up before? You can also use Mac data recovery software like iBoysoft Data Recovery for Mac to recover lost data from the unmountable external hard drives.

iBoysoft Data Recovery for Mac is afree external hard drive data recovery tool that enables you to recover lost data from external drives, especially when a hard drive is unmounted, formatted, inaccessible, unreadable, or corrupted. It's fully compatible with macOS Catalina 10.15/Mojave 10.14/High Sierra 10.13/10.12 and Mac OS X 10.11/10.10/10.9/10.8/10.7. In addition to external hard drive data recovery, it also can recover lost data from internal Mac hard drives, USB flash drives, SD cards, memory cards, pen drives, etc.

Tutorial to recover lost data from unmountable external drive on Mac with iBoysoft Data Recovery for Mac

Step 1: Download and install iBoysoft Data Recovery for Mac on Mac.

To use iBoysoft Data Recovery for Mac, you need to install this software on your Mac. You can just download the installation package and install it with no fuss.

Step 2: Launch iBoysoft Data Recovery for Mac.

After successfully downloading this program on your Mac, you can drag it to your Applications folder to install it, or you can double-click its icon to launch it.

Step 3: Select the unmountable external drive and click Scan button to scan all lost data.

When the Mac data recovery software is launched, all connected storage devices will be listed in the interface. You can see the name, file system, and space allocation of your hard drives and partitions. Locate your unmounted external hard drive, select it, and click 'Scan' to scan for lost data. Two scanning modes are allowed: Quick scan and Deep scan. Quick scan mode saves time for users and is applied when data is recently deleted. Deep scan mode finds more files at the cost of more time, and it's used when file system is corrupted or partition table is lost. Anyway, this software will automatically choose the most efficient way to scan for files according to the disk condition.

Step 4: Preview the searching results, choose files you need, and click Recover to get them back.

With the preview feature, you can check whether your files on this unmountable disk are in a good condition or not. It saves time and money for users. The software will show if your file is corrupted so that you would not waste energy to recover it or pay for this data recovery product.

Step 5: Have a check to ensure you have got all lost data back.

Unable To Mount External Hard Drive Mac Compatible

Mount Drive Mac Os

Now you either have a copy of a data backup in hand, or have recovered your important files with iBoysoft Data Recovery for Mac. Therefore, you can go ahead to repair this unmounted external drive without worrying about data loss.

Solution 3: Repair the external hard drive with Disk Utility

When an external hard drive is not working properly, you can use the built-in disk repair tool - First Aid to check and repair disk errors.

Step 1: Launch Disk Utility.

Step 2: Choose the unmountable external drive on the left sidebar.

Step 3: Select First Aid in the top center and click Run.

Solution 2: Repair the external hard drive with Terminal

Sometimes, Disk Utility may not function as desired. Fortunately, you can still try to repair the corrupted external hard drive with Terminal.

Step 1: Go to Applications > Terminal

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

Step 3: Check the volume identifier from the table that appears.

Step 4: Enter:diskutil repairVolume [diskvolume identifier]. For example, if the volume identifier of an external hard drive is disk2s, you should enterdiskutil repairVolume disk2s.

Solution 3: Reformat the external hard drive

If yourexternal hard drive can't be repaired with Disk Utility and Terminal, the file system of this drive might be seriously corrupted. The only way to fix this unmountable external drive is to reformat it.

Warning: Reformatting will erase all data on the external hard drive, so please make sure you have backed up important data.

1. Launch Disk Utility from Utilities.

2. Click the icon of the unmountable external drive on the left part of the window.

3. Click the Erase function on the top of the Disk Utility window.

Unable To Mount External Hard Drive Mac Not Recognized

4. Complete the related information (name, format, scheme), then click Erase button.


When you can't mount an external hard drive on your Mac, you can try the 5 methods introduced in this post. But no matter which solution you are going to try, to avoid data loss, you are always advised to back up your files or recover your data from this unmountable drive first with iBoysoft Data Recovery for Mac.

Mac Os X Download

But if unfortunately, none of these solutions can make your hard drive work again, or your disk is not even detected or showing up in Disk Utility, then this drive might be physically damaged. Under this situation, you should send it to a local disk repair service and see if they can help.

Good luck!

My Mac Mini w/ Fusion Drive (that’s a hard disk and an SSD pretending to be a single volume for better performance) froze and wouldn’t boot. Nothing would make it boot normally again. Recovery mode was OK but couldn’t erase the boot volume nor mount it via Disk Utility (I just got “Unable to delete the core storage logical volume”), so reinstalling seemed impossible.

Another suggestion added by a reader (thank you, Markus!) is that filesystem errors on your main Mac drive could be the cause of the disk image mounting errors. Here are instructions from Apple for scanning and repairing errors using Disk Utility. Note that in order to scan and repair errors on your main Macintosh HD drive, you'll need to. I have been using a WD My Passport for Mac 1 TB external hard drive to store photos and lightroom catalogue. Yesterday I had problems with the catalogue and am unable to copy all the files to another external hard drive as there were faults noted. Sometimes I cannot 'see' the hard drive from my macbook pro.

Unable To Mount Drive For Repair Mac Osx

Fortunately, I figured out how to do it, using some help from a StackExchange post I found. See below for the details.

Hard Drive Not Mounting Mac

The magic incantation that fixed it was inspired by instructions I found here:

Note: THIS WILL WIPE YOUR HARD DISK. Only do this if you’re completely ready to just burn it all down to the ground and start over with a blank boot disk.

Unable To Mount External Hard Drive Mac Computer

Here are the steps:

  1. Boot the recovery volume, which will take you to an OS X Utilities page that shows four options: “Restore From Time Machine Backup”, “Reinstall OS X”, “Get Help Online”, and “Disk Utility”. If you have gotten to this article you have probably already been into Disk Utility a few times already without success, so don’t open Disk Utility.
  2. From the Utilities menu of the “OS X Utilities” app, open Terminal. (Maximize the terminal window that opens so it’s easier to see the output of the next step.)
  3. Run diskutil cs list . Using the mouse, copy the long alphanumeric string that’s on the third line of output after “Logical Volume Group”. That’s the Logical Volume Group’s universally unique identifier, a.k.a. its “lvgUUID”.
  4. LAST WARNING: FROM HERE ON OUT THIS DELETES ALL OF THE DATA ON THE HFS+ LOGICAL VOLUME (but it doesn’t delete the recovery partition).
    Run diskutil cs delete FOO-BAR-BIZ-BAZ, where FOO-BAR-BIZ-BAZ was your lvgUUID. This deletes the logical volume group. diskutil will print things about erasing the physical partitions that made up the logical volumes, which in my case were /dev/disk0s2 (a 931GB partition on the internal hard disk) and /dev/disk1s2 (a 113GB partition on the internal SSD). Pay attention to the names of the devices that it just liberated on your system, since you’ll use those device names in the next step.
    At this point you have two empty HFS+ partitions that are not a Fusion drive anymore, so you’ll want to rebuild the LVG from those two physical partitions.
  5. Run this: diskutil cs create'Macintosh HD'/dev/disk0s2/dev/disk1s2 and adjust the /dev/.. stuff to include the partitions that diskutil said it erased & mounted in the prior step.
    On my Mac Mini it took about a minute to finish.
    At this point if you run diskutil cs list you should see just a Logical Volume Group and as many Physical Volumes as you added (which is two in my case, disk0s2 and disk1s2), without any Logical Volumes yet.
  6. Quit Terminal.app and run Disk Utility from the main “OS X Utilities” app.
    Disk Utility should show “Fusion Drive” without any partitions in it, which is expected since we just created the Logical Volume Group without any Logical Volumes in it.
  7. Select the Fusion Drive and run First Aid on it.
    First Aid will immediately create a Logical Volume and format it, leaving one big partition of type”OS X Extended (Journaled)” named “Untitled”.

Now you’re free to do whatever you want with this empty disk. In my case, I erased it and created a new partition named “Untitled” of type “OS X Extended (Journaled, Encrypted)” since I want full-disk encryption.

Mount External Drive On Mac

Lacie Hard Drive Not Mounting On Mac

(I tried to call it “Macintosh HD” during the erase step, but Disk Utility failed to erase the disk and complained that name was invalid, so I just left it as “Untitled”, erased the disk, and then renamed it by selecting the Untitled volume in the left-hand-side list of devices, then clicking on the right-hand-side pane where the name Untitled was shown and editing it there.)

Unable To Mount Drive For Repair Macbook Pro

Hard Drive Not Mounting On Mac

After this, I quit out of Disk Utility, and ran the “Reinstall Install OS X” app. That does a network install which first required me to log in with my Apple ID and then downloaded the install files.