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.
Oct 24, 2020 Your Seagate external hard drive connects to your Mac by its USB cable. The Seagate portable drives receive their power from your Mac by the USB cable. And that means you'll have to have enough battery power in your MacBook. Enough to power your Seagate external hard drive.
Moog plugin mac. 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.
- External Hard Drive on Mac Won't Mount. I accidentally unmounted the External Hard Drive and now I want to re-mount it back. Cannot reformat or unmount external.
- I copied all my data from the external drive to the Mac upgraded to a clean installation of HS. Then set the new Mac to restore back to the external drive using CCC. Halfway through the backup it failed - and now can't be read by anything. I plugged second working external drive (Mac-extended), and it won't show up.
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?'
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.
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.
Also, here are some things you can try.
- 1. Reconnect your external hard drive to your Mac and ensure that it fits the USB port snugly.
- 2. Connect the external hard drive to a different USB port or a different Mac.
- 3. Replace the USB cable or adapter in case that it was damaged or broken.
- 4. 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. Then you can go with 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.
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 a free 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 Big Sur 11/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 Pro engineer mac download.
- 1. Download and install iBoysoft Data Recovery for Mac on Mac, and then restart the computer.
- 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.
- 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.
- 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.
- 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.
- 5. Have a check to ensure you have got all lost data back.
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
Mount External Drive On Macbook Pro
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.
- 1. Launch Disk Utility.
- 2. Choose the unmountable external drive on the left sidebar.
- 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.
- 1. Go to Applications > Terminal
- 2. Enter: diskutil list (This will list out the available volumes).
- 3. Check the volume identifier from the table that appears.
- 4. Enter: diskutil repairVolume [diskvolume identifier]. For example, if the volume identifier of an external hard drive is disk2s, you should enter: diskutil 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.
- 4. Complete the related information (name, format, scheme), then click Erase button.
Conclusion
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.
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!
Mount Drive Windows 10
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 FreeFortunately, 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.
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.
How To Mount External Drive On Mac
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.
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.
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.
Also, here are some things you can try.
- 1. Reconnect your external hard drive to your Mac and ensure that it fits the USB port snugly.
- 2. Connect the external hard drive to a different USB port or a different Mac.
- 3. Replace the USB cable or adapter in case that it was damaged or broken.
- 4. 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. Then you can go with 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.
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 a free 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 Big Sur 11/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 Pro engineer mac download.
- 1. Download and install iBoysoft Data Recovery for Mac on Mac, and then restart the computer.
- 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.
- 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.
- 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.
- 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.
- 5. Have a check to ensure you have got all lost data back.
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
Mount External Drive On Macbook Pro
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.
- 1. Launch Disk Utility.
- 2. Choose the unmountable external drive on the left sidebar.
- 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.
- 1. Go to Applications > Terminal
- 2. Enter: diskutil list (This will list out the available volumes).
- 3. Check the volume identifier from the table that appears.
- 4. Enter: diskutil repairVolume [diskvolume identifier]. For example, if the volume identifier of an external hard drive is disk2s, you should enter: diskutil 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.
- 4. Complete the related information (name, format, scheme), then click Erase button.
Conclusion
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.
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!
Mount Drive Windows 10
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 FreeFortunately, 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.
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.
How To Mount External Drive On Mac
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.