Your Mac not recognizing an external hard drive can be cause for panic. But try to remain calm — it's unlikely that anything has happened to your files. All of your data will still be on the hard drive, it just that, for whatever reason, you can't access it.
Just so that you worry not about losing data, get Disk Drill. Available via Setapp, the app is the best tool that will rescue your files.
Download Disk Drill FreeNote: Safely remove and connect Mac hard drive that is not mounting to healthy Macintosh computer as external hard drive after installing this tool. At first download Yodot Mac Data Recovery software and install it to your Mac computer; Upon installing, run it to begin the recovery of files from Mac hard drive that wont mount. 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. If this is not the first time you're using an external hard drive and experiencing such a problem, it is not likely to be an issue for you. However, you could still check your preferences — just in case. Your settings might not be set to display external hard drives on your desktop. To fix that, go to Finder and click on the Finder button.
- Check Apple's Disk Utility to see if an external drive is showing up. Disk Utility is within System Preferences, or you can find it using Spotlight. If it is visible, then click the option to Mount, which should make it visible on the desktop and in the External Drives option in the Finder menu.
- I recently bought a 4 TB naked (no enclosure) external hard drive that I mount via a Newer Tech dock (the ones where you insert the naked drive like bread in a toaster) and is connected to my MacBook pro via FireWire 800. About a month later I wanted to use the drive and it would not mount. Disk Utility reports that it is 'Not Mounted'.
Fortunately, there are ways and means of getting the hard drive back up and running. Let's get into some of them right now.
Why a flash drive is not showing up on Mac?
If you've plugged in a flash drive or USB drive and it's not showing up on your Mac at all, it could be down to a faulty cable or USB port.
Before you try any system troubleshooting tips, start with the basics.
- Check that the drive is probably plugged in.
- Check the USB connector — does it look damaged or misshapen in any way?
- Check the cable — is it frayed or are there any wires exposed?
- If the external hard drive is plugged into a wall outlet, try a different outlet.
- Try a different USB cable — even cables with no visible defects can fail.
- Try connecting the hard drive to a different USB port — it could be a hardware issue.
- Try the drive in another Mac — if it works there, the problem is with the USB ports on your Mac.
- Test the hard drive on a PC — it could be formatted for PCs and not readable on Macs.
- Reboot your Mac — a simple on and off is sometimes all it takes.
- Reboot USB drives by shutting down your system and restarting it, holding Command+Option+P+R as you do. When you hear a sound and see the screen flash, release the keys and let your Mac boot up as usual.
If you've carried out visually inspections, tested your hard drive with different cables and power outlets, and tried different systems with no luck, it's time to put your Mac to work.
Mac Os External Hard Drive Not Mounting System
1. Change the Finder settings
One of the most common reasons for Mac not recognizing external hard drives is due to the system not being set up to display hard drives on the desktop. There's a simple fix for this:
- Open a Finder window.
- Go to Preferences > General.
- Check that the External disks option is enabled.
If your Mac is not recognizing a USB or external hard drive after this, you'll have to try mounting it manually.
2. Mount an external hard drive on Mac
If Mac isn't automatically recognizing your external hard drive, it's time to force it to. Connect your hard drive and follow these instructions:
- Go to System Preferences > Disk Utility.
- Check that the external disk is listed in the left sidebar.
- Highlight your hard drive and select Mount. It should now appear under devices in the Finder.
If the hard drive still isn't playing ball, the next step is First Aid.
3. Run First Aid on an external hard drive
Mac's built-in First Aid tool is designed to verify and repair a range of issues related to corrupted files and apps, startup issues, and, crucially, external hard drive problems.
If your issue has to do with wanting to know how to open a flash drive on Mac that's displaying but not allowing you access to files, First Aid might be able to help.
- Go to System Preferences > Disk Utility.
- Highlight your external hard drive and click on First Aid.
- Select Run to start running diagnostics and prompt Mac to automatically fix any issues.
If First Aid is successful in repairing any faults, your hard drive should be available to mount. If not, you'll need to try the next option.
4. Delete potentially conflicting apps
How recent is the problem? If a flash drive not showing up on Mac was completely fine a few days earlier there could be an app causing conflict. If you've downloaded any new apps recently, uninstall them one at a time, connecting your hard drive after each uninstallation to see if the issue is resolved.
You can delete apps using the Launchpad or by dragging them to the Trash, but neither method is recommended in this situation. You see, while an app might appear to be deleted, associated files will be left on your system — files that could be preventing access to your external hard drive.
Instead, let CleanMyMac X take care of it. CleanMyMac X has an Uninstaller tool that can define your installed applications and associated files and remove every trace of an unwanted app.
And it couldn't be easier to use.
- Download CleanMyMac X (for free).
- Launch the app and select Uninstaller.
- Click on View All Applications and select a recently installed app.
- Click Uninstall.
If you've worked through all recently installed apps and are still no further forward, your hard drive may have crashed or, worse, be completely broken. In this case, you'll need a heavy duty tool like Disk Drill to rescue files.
5. Repair disk permissions
Disk permissions keeps your files secure. Every file and folder has an associated set of permissions. Unfortunately, these can get messed up without you realising it, which can cause serious problems. You can fix these two ways. Either manually, as we mention in this article, or using CleanMyMac X, which is far easier.
All you need to do is:
- Click on Maintenance from the left sidebar menu.
- Check the box next to Repair Disk Permissions.
- Click Run.
The program will scan and fix any it finds that are broken or faulty. Your Mac should be running as good as new.
To prevent an external hard drive not showing up on Mac turning into an all-out disaster, always backup files on your system hard drive and in the cloud. Anytime you use an external drive, unmount the disk properly and store it safely. And finally, use CleanMyMac to uninstall apps and run regular Maintenance on your system to prevent applications conflicting with hard drive performance.
These might also interest you:
Summary: External hard drive not mounting on Mac means that you can't access data stored on it. This page helps you mount external hard drives, as well as SD cards and USB flash drives, etc. on Mac. If the external hard drive won't mount on Mac, you can download iBoysoft Data Recovery for Mac to recover lost data from unmountable external hard drives.
Usually, an external hard drive will appear (aka mounted) automatically on your Mac once you plug it in, and you can access data on this drive. So, it's annoying when you find that your external hard drive is not mounting for the com.apple.DiskManagement.disenter error or not recognized by your Mac, just like the user below.
'I have a 500 GB LaCie external hard drive, formatted as macOS Extend journaled on MacBook Pro 2014 and I have been using it to do Time Machine backups. Now after updating, macOS is not mounting this external hard drive. The main drive is greyed out in Disk Utility and the partition is not showing up. I can't do First Aid as my LaCie external drive does not mount on the MacBook Pro. Any ideas? Thanks!'
Wondering 'why my external hard drives won't mount on Mac'? This post explains the reasons and teachs how to fix this disk problem without losing data.
Dos and Don'ts When External Hard Drive Not Mounting on Mac
Before you go further, it's better to know what you can do and can't do.
1. Do not go straight to reformat this not mounted external hard drive, especially when you have important files on it. Reformatting will wipe the data on this disk and cause serious data loss.
2. Do not run First Aid to directly repair the disk, any further operation is very likely to overwrite your original files and make them unrecoverable.
3. Check if you have a copy of a data backup. If not, recover important files from this unmountable external hard drive first to avoid data loss.
And it couldn't be easier to use.
- Download CleanMyMac X (for free).
- Launch the app and select Uninstaller.
- Click on View All Applications and select a recently installed app.
- Click Uninstall.
If you've worked through all recently installed apps and are still no further forward, your hard drive may have crashed or, worse, be completely broken. In this case, you'll need a heavy duty tool like Disk Drill to rescue files.
5. Repair disk permissions
Disk permissions keeps your files secure. Every file and folder has an associated set of permissions. Unfortunately, these can get messed up without you realising it, which can cause serious problems. You can fix these two ways. Either manually, as we mention in this article, or using CleanMyMac X, which is far easier.
All you need to do is:
- Click on Maintenance from the left sidebar menu.
- Check the box next to Repair Disk Permissions.
- Click Run.
The program will scan and fix any it finds that are broken or faulty. Your Mac should be running as good as new.
To prevent an external hard drive not showing up on Mac turning into an all-out disaster, always backup files on your system hard drive and in the cloud. Anytime you use an external drive, unmount the disk properly and store it safely. And finally, use CleanMyMac to uninstall apps and run regular Maintenance on your system to prevent applications conflicting with hard drive performance.
These might also interest you:
Summary: External hard drive not mounting on Mac means that you can't access data stored on it. This page helps you mount external hard drives, as well as SD cards and USB flash drives, etc. on Mac. If the external hard drive won't mount on Mac, you can download iBoysoft Data Recovery for Mac to recover lost data from unmountable external hard drives.
Usually, an external hard drive will appear (aka mounted) automatically on your Mac once you plug it in, and you can access data on this drive. So, it's annoying when you find that your external hard drive is not mounting for the com.apple.DiskManagement.disenter error or not recognized by your Mac, just like the user below.
'I have a 500 GB LaCie external hard drive, formatted as macOS Extend journaled on MacBook Pro 2014 and I have been using it to do Time Machine backups. Now after updating, macOS is not mounting this external hard drive. The main drive is greyed out in Disk Utility and the partition is not showing up. I can't do First Aid as my LaCie external drive does not mount on the MacBook Pro. Any ideas? Thanks!'
Wondering 'why my external hard drives won't mount on Mac'? This post explains the reasons and teachs how to fix this disk problem without losing data.
Dos and Don'ts When External Hard Drive Not Mounting on Mac
Before you go further, it's better to know what you can do and can't do.
1. Do not go straight to reformat this not mounted external hard drive, especially when you have important files on it. Reformatting will wipe the data on this disk and cause serious data loss.
2. Do not run First Aid to directly repair the disk, any further operation is very likely to overwrite your original files and make them unrecoverable.
3. Check if you have a copy of a data backup. If not, recover important files from this unmountable external hard drive first to avoid data loss.
Now, let's make the external disk accessible on Mac.
Fix external hard drives not mounting issue on Mac
To access your external hard drive on Mac, try solutions suggested in this part one by one. Hopefully, you'll be able to open this external hard drive on Mac again.
First, try some simple tricks to mount external hard drive on Mac
In case you miss anything necessary, you can first have some basic checks as following:
1. Re-plug your external hard drive to another port or try another USB cable.
A faulty connection, though it is foolproof, might be the key fix if LaCie thunderbolt drive is not mounting, in that users always forget to check if the port is wobbly or if the cable is broken.
2. Try a super slow jam.
Strange but true, some users found that their external will mount properly when they plug it in exceptional slow motion. However, if they try and plug in the external hard drive normally, the Mac doesn't recognize the disk.
3. Check your Finder Preferences.
When your external hard drive does not appear on the desktop, you can open Finder, choose 'Preference' (or press Command +, ) and check 'External disks' both in General tab and in Sidebar tab to show your external hard drive on your Mac computer.
If Mac could not mount the external hard drive on desktop still, let's troubleshoot this issue with the following solutions.
Solution 1: Force mount this external hard drive in Disk Utility
If you can't find the external hard drive on the desktop or in the Finder, you can try to make the disk online manually in Disk Utility (a native disk management tool in your Mac).
Here is how to mount an external hard drive on Mac:
- 1. Click Go at the upper left of your desktop and go to Utilities, then launch Disk Utility on your Mac computer.
- 2. Click on 'Show All Devices' in View option to list or connected drives.
- 3. Choose the grayed external hard drive in the left sidebar.
- 4. Select Mount in the top center of Disk Utility.
However, if you find that your external hard drive is not showing up in Disk Utility (not a single volume but the whole disk disappears), it is very likely that your disk is suffering some physical damage. In this case, you need to send it to a local data recovery service. But if the Mount option is grayed out and you can see this external hard drive in Disk Utility, you can try another solution then.
Solution 2: Repair this unmountable external hard drive with First Aid
The second suggestion is First Aid in Disk Utility if you are unable to mount the external hard drive on Mac. First Aid is a very simple tool that is built in your Mac, and it is able to detect and repair directory damage and other disk errors. You are advised to run the tool more than once to ensure you are receiving a consistent result.
Best Backup Drive For Mac
Follow the instructions and repair the external hard drive that is not accepted by your macOS or Mac OS X.
- 1. Go to Utilities and launch Disk Utility on your Mac computer.
- 2. Select the unmountable external hard drive on the left sidebar.
- 3. Select First Aid in the top center and click Run.
Solution 3: Reformat the unmounted external hard drive
If your external hard drive still can't be mounted in Disk Utility after you perform First Aid, or if First Aid failed to repair it like the situation below, your drive should have some serious errors like file system corruption.
• Disk Utility can't repair this disk, what do to?
• How to format external hard drives on Mac?
In this case, you need to back up your important data on the external hard drive, such as family photos, valuable work documents, or any other files. If you don't have a copy of a data backup in hand, the following guide can help you recover lost data from this unmountable external hard drive. And then, you can reformat your exteranl hard drive to make it work again on Mac.
How to recover data from an external hard drive that won't mount?
As long as your external hard drive doesn't have any hardware problem, fortunately, you can retrieve your files with professional Mac data recovery software - iBoysoft Data Recovery for Mac with no fuss.
Best External Hard Drive Data Recovery - iBoysoft Data Recovery for Mac
- Recover lost data from unmountable, formatted, inaccessible, unreadable, corrupted external hard drives.
- Supported storage devices: external hard drives, USB flash drives, memory cards, SD cards, etc.
- Supported file types: photos, videos, audio files, documents, emails, etc.
- Suppported Mac OS: macOS Big Sur 11/10.15/10.14/10.13/10.12 and Mac OS X 10.11/10.10/10.9/10.8/10.7.
Read-only & risk-free
Tutorial for external hard drive data recovery on Mac with iBoysoft Data Recovery for Mac
- 1. Free download and install iBoysoft Data Recovery for Mac on your computer, and then restart your Mac.
- 2. Launch iBoysoft Data Recovery for Mac.
- 3. Select the external hard drive that is not mounting and click Scan button to scan for all lost data.
- 4. Preview the searching results, choose files you need, and click Recover to get them back.
- 5. Have a check to ensure you have got all lost data back.
Note: You need to save the recovered files to another usable drive.
After having successfully restored all data on this drive, you can set out to erase this external hard drive to fix the disk not mounting on Mac issue.
Tutorial to reformat unmountable external hard drives on Mac
- 1. Launch Disk Utility.
- 2. Click the icon of your unmountable external hard drive on the left sidebar.
- 3. Click on the Erase button function on the top of the Disk Utility window.
- 4. Complete the related information (name, format, scheme), then click Erase button to finish reformatting.
After reformatting, your external hard drive will be assigned with a new file system so that you can mount this unmountable hard drive again.
Then, why we can't access the external hard drive on Mac?
Probably, the user above would never know why his MacBook is not mounting the external hard drive. As a matter of fact, this problem could be caused by many factors, such as damaged file system, virus attack, unsafe ejection or any other improper operations.
How to update mac if no updates are available. Here are some common ones.
- A damaged file system: If your external hard drive is attacked by virus or if you abruptly eject this drive, it's likely that the file system of this disk would be damaged or corrupted. As a result, the operating system is unable to recognize this disk, and the disk will not be mounted or read by macOS.
- Connection problems: Another reason that hard drive won't mount on Mac could be a dirty or loose connection between your cable, USB-C multi-adapter, Thunderbolt 3, or other connecting ports. A clear, clean, snug and fit tightly connection is the premise of mounting an external hard drive successfully.
- Hardware issue: Also, problems related to hardware could also make the disk unmountable, especially when your external hard drive has too much bad sectors or have been physically damaged.
Knowledge Base: What does 'Mount' mean on Mac?
Mounting an external hard disk means the macOS gives a mount point (entrance) to read and access information on the hard drive. Information is accessed by the disk file system and partition table. So, it's a necessary step before the operating system can access a disk (including read from and write to).
Therefore, if an externalhard drive won't mount on Mac, it means the system gets into trouble in recognizing the file system or other information of this hard drive.
Conclusion:
If your external hard drive is not mounting on your Mac, don't panic. Most of the time, you are going to fix this disk problem with the solutions above. Moreover, if you worry about data loss when the disk becomes unmountable, you can use iBoysoft Data Recovery for Mac to recover your files first. Remember that, no matter what disk problem you meet, you should perform hard drive data recovery in case of losing data.
