What to Do When Your External Hard Drive Won’t Mount on Mac

External hard drives are a convenient way to add storage or backup files on your Mac. But when your drive doesn’t mount, it can be a real problem. Without access to the drive, you can’t use it for file transfers, backups, or anything else. In this guide, we’ll walk you through ways to fix the issue when your external hard drive isn’t mounting on your Mac.

Why is My External Hard Drive Not Mounting on my Mac?

Several issues can cause your external hard drive not to mount on your Mac. Sometimes, it’s as simple as a loose connection. Other times, the problem can be more complex.

Here’s a rundown of what might be going on:

• Improper connections. A loose or damaged cable can prevent your Mac from recognizing the external drive. Testing the connection with a different cable or USB port can help identify the issue.
• Finder settings. If Finder isn’t set to show external drives, the device might be connected but hidden. A quick settings adjustment can fix this.
• Corrupted file System. If the file system on your external hard drive is corrupted, macOS might fail to mount it. This often happens if the drive was improperly ejected or if it experienced a sudden power loss.
• Drive failure. Physical damage or internal faults in the drive can prevent it from mounting. If the drive shows signs of failure, like unusual noises or overheating, you might need professional data recovery services.
• Incompatible file system. If your external hard drive is formatted with a file system that macOS doesn’t natively support — like NTFS — it won’t mount automatically. macOS can read NTFS drives but cannot write to them without third-party software. To make the drive fully usable, you may need to reformat it to a compatible file system such as APFS, Mac OS Extended, or ExFAT.

🚩 Important. Before reformatting, recover your data first, since formatting will wipe everything. Check the “How to Recover Data from an External Hard Drive That Won’t Mount on Mac” section of this article for steps on how to do that.

How to Fix an External Hard Drive Not Mounting on a Mac

Now that you know the potential causes, let’s get into the steps you can take to fix the issue. These methods will help you troubleshoot the problem and, in many cases, get your external hard drive mounted on your Mac.

Method 1: Check Connections and Cables

The first thing to check when your external hard drive isn’t mounting on your Mac is the connection. Often, a simple hardware issue can be the culprit.

Here’s what to do:

1. Unplug the drive and check the cable for visible damage. Look for any fraying, kinks, or bent connectors that might be causing issues. If possible, use a different cable to rule out cable damage.
2. Try plugging the drive into another USB port on your Mac. Ports can wear out or malfunction over time, so testing a different one might help identify the problem.
3. If you’re using a USB hub, connect the drive directly to your Mac instead. Hubs can sometimes cause power or data transfer issues, particularly with older or heavily used ones.
4. If your external hard drive requires its own power supply, make sure it’s properly connected and powered on. Drives that don’t get enough power won’t mount.

Method 2: Restart Your Mac

If checking the connections didn’t resolve the issue, restarting your Mac can help. A system restart clears temporary glitches and refreshes your Mac’s connection with external devices. Here’s how to do it:

1. Click on the Apple logo in the top-left corner of your screen and select “Restart.” Confirm the action and wait for your Mac to reboot.

2. Once your Mac restarts, reconnect your external hard drive and see if it mounts. This simple step often resolves issues caused by system hiccups.

3. Sometimes, having too many applications open can interfere with your Mac’s ability to properly detect and mount external devices. Make sure to close any unneeded apps before connecting the drive.

Method 3: Adjust Finder Settings

Sometimes, the issue could be that your Finder app isn’t set to show external drives. This is a quick setting adjustment that might solve the problem. Here’s how to check and fix it:

1. Click on Finder in the top-left corner of your screen and choose “Settings” from the dropdown menu.

2. In the “General” tab of Finder Preferences, check the box next to “External disks.” This setting makes external drives visible on your desktop.

3. Switch to the “Sidebar” tab in Finder Preferences. Under the “Locations” section, make sure “External disks” is checked here as well. This will make your external hard drive easily accessible from the Finder sidebar.

After adjusting these settings, reconnect your external hard drive and see if it appears on your desktop or in the Finder sidebar.

Method 4: Use Disk Utility to Mount the Drive

If that didn’t help, it’s time to turn to Disk Utility. Disk Utility is a versatile tool on macOS that lets you manage and repair disks, including external hard drives. We’ll be talking about Disk Utility a lot in this article because it’s one of the primary ways to troubleshoot drive-related issues on a Mac.

Here’s how to use it to manually mount your drive:

1. Navigate to Applications > Utilities and open Disk Utility. This app lets you see all connected drives, even those that aren’t currently mounted.

2. In the sidebar, look for your external hard drive. If the drive is listed but not mounted, you can try mounting it manually.

3. Select the drive and click the “Mount” button at the top of the window. If Disk Utility can mount the drive, it should now appear in Finder.

If the drive doesn’t mount or Disk Utility shows an error message, this may indicate a problem with the file system on the drive. Disk Utility includes tools to help fix these kinds of issues, which we’ll cover in the next method.

Method 5: Repair the Drive with First Aid

Let’s try using Disk Utility’s First Aid tool. First Aid checks your external hard drive for file system errors and attempts to fix them. This tool is handy when your drive isn’t mounting because of corruption or other software issues.

🚩 Note. If you have important files on the drive that you can’t afford to lose, running repairs could make things worse if the file system is severely damaged. In cases like this, we recommend checking the “How to Recover Data from an External Hard Drive That Won’t Mount on Mac” section of this article first. There, you’ll find steps to recover your files before attempting any repairs. It’s always safer to retrieve your data before making any changes to a problematic drive.

Here’s how to use First Aid in Disk Utility:

1. If you’re not already there, go to Applications > Utilities and open Disk Utility.

2. In the sidebar, find your external hard drive. Even if the drive isn’t mounted, it should still appear in the list.

3. Click on your drive, then hit the “First Aid” button at the top. Disk Utility will ask for confirmation — click “Run” to start the repair process.

4. Disk Utility will scan the drive for issues and try to repair them. This can take a few minutes, depending on the drive’s condition. Once it’s done, you’ll get a report on whether the repair worked.

If First Aid fixed the problem, try mounting the drive again through Disk Utility.

Method 6: Reset SMC and NVRAM

For some older Mac models, resetting the SMC (System Management Controller) or NVRAM (Non-Volatile Random-Access Memory) can help with hardware issues, including problems with external hard drives not mounting. This method is particularly useful for Intel-based Macs, such as MacBook Pro (pre-2018), MacBook Air (pre-2018), iMac, and Mac mini models that do not use Apple’s M1 chip.

🚩 Note for M1/M2 Mac users. If you have a newer Mac with an M1 or M2 chip, you don’t need to reset the SMC or NVRAM. Apple Silicon Macs manage these functions automatically, making manual resets unnecessary. In these models, a simple restart handles most hardware-related issues.

How to reset SMC on MacBook (Non-M1 Models):

1. Turn off your Mac completely.
2. For MacBook Pro or MacBook Air models with non-removable batteries (pre-2018), hold down Shift + Control + Option on the left side of the keyboard and press the power button simultaneously.
3. Keep holding the keys and power button for 10 seconds, then release them.
4. Press the power button again to turn your Mac back on.

How to reset NVRAM on all Intel Macs:

1. Turn on your Mac and immediately press and hold Option + Command + P + R.
2. Continue holding the keys for about 20 seconds. Your Mac may restart during this process.
3. Once you release the keys, let your Mac start up normally. Resetting the NVRAM clears system settings that could affect hardware recognition, like sound volume or startup disk selection.

Method 7: Use Terminal for Advanced Mounting Fixes

Now, we’ll show methods for those familiar with Terminal commands. Terminal is a tool on macOS that lets you interact with your system through command-line instructions. If you’ve never used it before, that’s okay. We’ll go into enough detail so you can follow along and try these steps on your Mac.

Here’s how to do it:

1. Go to Applications > Utilities and open Terminal. This opens a blank window where you can type commands.

2. Type “diskutil list” and press Return. This command will list all drives connected to your Mac, including unmounted ones. Look through the list to find your external hard drive, which will be labeled something like /dev/diskX, where X is the number representing your drive.

3. Once you’ve identified your drive, type “diskutil mount /dev/diskX”, replacing diskX with the correct identifier for your drive, and press Return. If successful, your drive should now mount and be visible in Finder.

💡 Restart the USB daemon. If the drive still doesn’t mount, restarting the USB daemon might help. Type “sudo launchctl stop com.apple.usbd” and press Return, followed by “sudo launchctl start com.apple.usbd”. This action restarts the system’s USB management service, which can sometimes resolve connection issues.

If the Terminal can’t mount the drive or returns an error, it may indicate deeper file system problems. At this point, reformatting the drive might be necessary.

Method 8: Reformat the External Hard Drive

If none of the previous methods worked, reformatting the external hard drive might be the final option. Reformatting will erase everything on the drive, so make sure to recover any important data first. You can find detailed instructions on how to recover your files in the “How to Recover Data from an External Hard Drive That Won’t Mount on Mac” section of this article.

For reformatting, we’ll use Disk Utility, which we’ve already discussed in previous methods. Here’s how to do it:

1. Open Disk Utility.

2. In the sidebar, find your external hard drive. Even if it isn’t mounted, it should still appear in the list.

3. With the drive selected, click the “Erase” button at the top of the window. A dialog box will appear, allowing you to choose settings for reformatting.

4. For use with macOS, select APFS or Mac OS Extended (Journaled). If you need the drive to work with both macOS and Windows, choose ExFAT.

5. Enter a name for the drive, and click “Erase” to start the process.

6. Disk Utility will erase and reformat the drive. Once finished, the drive should automatically mount and appear in Finder.

How to Recover Data from an External Hard Drive That Won’t Mount on Mac

If your external hard drive is visible in Disk Utility, even if it’s not mounting, there is a way to retrieve your files using data recovery software. For this article, we will show you how to use one of the most popular data recovery tools: Disk Drill. Developed by CleverFiles, Disk Drill has earned its reputation for a reason. It’s widely recognized for its effectiveness in recovering lost files, regardless of how tech-savvy you are.

Disk Drill supports a wide range of file systems, including those that macOS doesn’t natively recognize, such as NTFS, FAT32, and others. This means that even if your external hard drive is formatted with a Windows file system, Disk Drill can still help you recover your data.

🚩 Note. Disk Drill offers a free version that allows you to preview recoverable files. However, to actually recover the files, you’ll need to upgrade to one of the paid versions. If you’re looking for free alternatives, you can check out our article on FREE Data Recovery Software for Mac for other options.

Here’s how to recover your data using Disk Drill:

1. Download and install Disk Drill.

2. Launch the program from your Applications folder after installation.

3. Plug your external hard drive into your Mac, even if it doesn’t mount. Disk Drill can detect drives that aren’t accessible through Finder.

4. Once connected, your external hard drive should appear in Disk Drill’s list of available devices.

5. Select your external hard drive and click “Search for lost data.” Disk Drill will begin scanning the drive for recoverable files. The scan may take some time depending on the size of the drive and the extent of the damage.

6. After the scan completes, Disk Drill will display a list of recoverable files. Preview the files to make sure they’re intact and match what you need.

7. Choose the files you want to recover by checking the boxes next to them in the Disk Drill interface.

8. Click the “Recover” button and select a safe location on your Mac to save the recovered files.

Once the recovery process is complete, check the files in the location you saved them to confirm that they were successfully recovered.

🚩 Note. If your external drive is an SSD, data recovery can be more challenging due to the way SSDs handle data storage and wear leveling. We recommend reading this article on SSDs to learn more about the specific challenges and considerations when recovering data from solid-state drives.

Final Words

We are confident that with the step-by-step guides in this article, you were able to fix the issue with your external hard drive not mounting on your Mac. Whether it was a simple connection problem or something more complex, these methods should help you get your drive working again. Moving forward, remember to back up your data regularly to avoid any potential data loss in the future.

FAQs

What does it mean when I’m unable to mount an external hard drive on a Mac?

When you’re unable to mount an external hard drive on your Mac, it means the operating system cannot access the drive’s file system. This could be due to connection problems, file system corruption, or the drive being in a format macOS doesn’t support.

What should I do if my Mac external hard drive is not mounting?

Start with basic troubleshooting steps like checking the cables and ports. If that doesn’t help, try adjusting Finder settings or using Disk Utility to manually mount the drive. If the drive still won’t mount, consider using Terminal or reformatting the drive, but only after recovering your important data.

How do I fix an external hard drive that won’t mount on Mac Disk Utility?

Open Disk Utility, find your external hard drive in the sidebar, and try to manually mount it by selecting the drive and clicking “Mount.” If Disk Utility shows errors, use the “First Aid” option to repair any file system issues that might be preventing the drive from mounting.

Can I fix a hard drive not mounting on a Mac without losing data?

Yes, you can fix a hard drive not mounting on a Mac without losing data by trying non-destructive methods first, such as running First Aid in Disk Utility or using Terminal commands. It’s important to recover any important data using tools like Disk Drill before attempting more drastic measures like reformatting.