External Hard Drive Is Not Mounting on a Mac: How to Fix

hard drive isnt mounting on mac

To access any drive through a computer, it needs to be properly mounted. By default, this process should happen in the background. If you are unable to mount an external hard drive on your Mac automatically (and you didn’t change any settings), something’s up.

Things like corruption and faulty connectors could be preventing your Mac from properly recognizing the drive. Depending on the culprit, your data may be in danger. This article will help you secure your data and teach you how to fix a hard drive that’s not mounting on a Mac.

Why is External Hard Drive Not Mounting on Mac

There are a few possible culprits why your external hard drive won’t mount on Mac. Some of them are easy enough to resolve, while others need immediate action to secure your data.

We divided these factors into two categories: Software-Based Causes and Hardware-Based Causes. This distinction is important not only for diagnosing your drive or your Mac, but also critically affects the next step of recovery.

Software-Based Causes

 
Software-based causes are considered “logical damage.” The physical components of your drive are unharmed but the settings and processes of either the storage device or your Mac malfunctioned in a way that prevents your drive from being mounted. In this scenario, users can usually restore and even fix their drives themselves.

  • You disabled the display settings – macOS allows users to show or hide external drives on the desktop and in finder. Check Disk Utility if your drive has an “Unmount” button – this means that your hard drive has been successfully mounted and is just hidden. We’ll show you how to enable the display settings later in the article.
  • Your drive is corrupted – Virus attacks and faulty software can cause corruption, as well as interrupting a drive while it’s reading or writing data (for example: yanking out your drive in the middle of transferring files).
  • macOS ran out of resources – Your Mac could have run out of resources while mounting your hard drive. It also could have lagged while refreshing itself, preventing your hard drive from properly getting mounted.
  • Your drive uses the wrong format – macOS only supports ExFAT, FAT32, HFS+ and APFS formats. If your drive uses other formats like NTFS or HFS+, you need to reformat it for macOS to recognize and mount it.

Hardware-Based Causes

Hardware-based causes refer to mechanical malfunction or physical damage to your drive’s components. Simple mechanical issues can sometimes be resolved by the user.

If your drive is physically damaged, trying to recover or fix it yourself will only make things worse. We highly recommend sending your drive to a professional data recovery center. They have the facilities, equipment, and specialists needed to restore your files without ruining your data.
  • Connectors are damaged -Dust and debris may be blocking your ports and connectors, preventing your Mac from properly recognizing your hard drive. Use a dry microfiber cloth to clean your equipment. Otherwise, try connecting your hard drive to another port or computer.
  • Your drive is physically damaged – Hard drives are vulnerable to extreme temperatures, waterlogging, and scratches – especially on its spinning disk. If you can’t mount your external hard drive on Mac after dropping your drive or leaving it on a very hot surface, it’s possibly physically damaged.

How to Recover Data From Drive That Isn’t Mounting

To recover data from a hard drive that is not mounting on a Mac, we can use data recovery software to extract files directly from the file system. As long as your external hard drive shows up in Disk Utility but won’t mount, this method will work – just make sure Disk Utility displays the correct size.

For this article, we’ll be using Disk Drill. It’s a well-known tool that’s super easy-to-use, which is why we often feature it in our articles to demonstrate data recovery. Here’s how to do it:

Step 1. Download and install Disk Drill.

Step 2. Launch Disk Drill (Finder > Applications > Disk Drill).
Disk Drill icon in the Finder Applications folder

Step 3. Select your hard drive from the middle pane, then click “Search for lost data.”
Disk Drill drive selection screen

Step 4. Wait for Disk Drill to complete its scan. Once it’s done, click “Review found items.”
Disk Drill scanning screen

Step 5. In this screen, you can use the search bar to quickly find the files you need. Or, you can use the left sidebar to filter the results.
Disk Drill search bar and file type sidebar

Step 6. To preview a file, hover your mouse beside its file name. An eye button should appear – click it.
Disk Drill hard drive file preview

Step 7. Tick the boxes beside the files you want to restore, then click “Recover.”
Disk Drill file selection

Step 8. Use menu or click “Choose folder…” to select a location on your computer where Disk Drill will save the recovered files. Then, click “Next”.
DIsk Drill save file dialogue

Disk Drill Basic for Mac does not offer free data recovery. However, it does offer free unlimited preview – this is super useful for determining if your data is recoverable. Free data recovery software does exist, but they all have their own limitations. Your mileage may vary.

How to Mount an External Hard Drive on Mac

Depending on what is preventing your external hard drive from being mounted on your Mac, there are different methods we can try to fix it.

Method 1: Change macOS Drive Display Settings

macOS allows its users to hide or display external devices in the Finder sidebar and on the desktop. If Disk Utility shows that your drive is actually mounted, this may be the culprit. Here’s how to access these settings:

Step 1. Open Finder. On the Apple menu bar, click Finder > Preferences.
Preferences button in the Finder menu

Step 2. In the “General” tab, tick the box beside “External disks.”
General tab in the Finder Preferences window

Step 3. In the “Sidebar” tab under the “Locations” section, tick the box beside “External disks.”
Sidebar tab in the Finder Preferences window

Method 2: Reconnect Your Drive

Maybe the connection just didn’t bite. Try reconnecting your drive… And while you’re at it, try different ports and cables too.

Method 3: Restart Your Mac

If you have a lot of apps running as you connect your drive, macOS might have run out of the resources needed to mount and read it. macOS could also have gotten stuck while refreshing itself in the middle of mounting your drive.

Restart your Mac to “unstuck” it, and avoid opening too many apps while you use your hard drive.

Method 4: Force Mount Your Drive With Disk Utility

Through Disk Utility, you can manually force mount an external hard drive on your Mac. Launch Disk Utility (Finder > Applications > Utilities), select your drive or drive volume, and click “Mount.”

Mount button in Disk Utility

Method 5: Use Disk Utility’s First Aid Tool

The First Aid tool is also a Disk Utility function. It can find and automatically repair disk errors depending on the severity. Launch Disk Utility (Finder > Applications > Utilities), select your drive, and click “First Aid.”

First Aid button in the Disk Utility window

Method 6: Reformat Your Drive

In most cases, reformatting your drive can be the most effective solution for resolving software-based mounting issues. This process wipes everything on your drive, including its file system settings, viruses, and any corruption that prevents the drive from communicating with your computer.

We’ll show you how to format your drive using Disk Utility on your Mac.

Since this process nukes your data, we suggest creating an image backup of your drive so data recovery software can extract its files later without copying its viruses or corruption. Disk Drill (the app featured in the recovery section) has a built-in feature that accomplishes this called Byte-to-byte backup.

Disk Drill byte-to-byte backup screen

  1. Connect your hard drive to your Mac and launch Disk Utility.
  2. Select your drive from the left sidebar and click Erase.
  3. Select New Name, Format and other options for your Drive
  4. Disk Utility erase dialogueClick Erase when prompted to confirm the action.

If your drive doesn’t show up in Disk Utility, it’s possibly using a file system format that macOS doesn’t recognize. For reference, supported formats are ExFAT, FAT32, HFS+, and APFS. In this case, reformatting is still the answer – but you need to do it on a computer that recognizes its existing file system.

Conclusion

All storage devices are prone to software malfunctions that prevent mounting. Fortunately, they’re often easy to solve on their own and you can use backups or data recovery software to retrieve your data. However, successfully fixing your drive depends on solving the root cause – so inspect your settings for any changes before using drastic methods like reformatting.

On the other hand, external hard drives are extra prone to mechanical and physical issues due to their moving parts. Make sure to carefully inspect your device before attempting recovery as these cases are better left to professionals.

FAQ

If your LaCie drive is not mounting on your Mac, try these fixes:

  • Reconnect your drive.
  • Restart your Mac.
  • Force Mount your drive using Disk Utility’s Mount tool.
  • Repair your drive using Disk Utility’s First Aid tool.
  • Reformat your drive.

Warning: Reformatting your drive will wipe the data on it. We suggest cloning your drive and using that clone as the target for data recovery tools. Disk Drill has both backup and recovery functions built in, so we recommend using it for this task.

When you connect your hard drive to your Mac, macOS establishes a connection with the drive and makes it available for access. This process is called “mounting” a disk. To “unmount” a disk means to kill the connection and remove access. The terms “mount” and “unmount” were first used to describe this process back when computers were more analog.
Yes, a hard drive needs to be mounted in order to be properly recognized by your computer.
Alejandro is Macgasm’s Chief Writer and Apple ecosystem enthusiast. He pens the majority of troubleshooting guides and software reviews for this website, tapping into his love for technology and extensive background in technical writing. He started his career by helping multi-regional manufacturing companies in his home country communicate their products and operations to prospective B2B partners. After growing his writing business, he has since worked for top SaaS companies and finance/fintech resources like AgentFire and moneyGenius. He also helped market tech products to angel investors as well as on platforms like Indiegogo and Kickstarter. He is currently learning Swift on his MacBook Pro M1 so he can develop his own pomodoro app for his iPad Pro 11 and 2nd generation 256GB iPhone SE. He also has a gaming PC where he still plays Skyrim with 250+ mods and a Samsung Galaxy smartphone so he can keep using the aux cord in his '95 Nissan.