If you want to know how to fix external hard drive won’t mount on Mac, this guide explains various troubleshooting methods to help you restore connectivity and access data on your external hard drives.
An external hard drive should appear on your Mac as soon as you connect it. If it does not mount, you may see problems such as the disk not showing up, not being recognized, or access being denied. This issue is common and usually caused by simple settings, connection problems, or disk errors. The good news is that most causes are easy to identify and fix without losing data.
Below is a clear overview of the most common reasons why an external hard drive will not mount on a Mac.
| Reason | What it means |
|---|---|
| Physical connection issues | The USB cable or port may be loose, damaged, or dirty, so the drive cannot connect properly. |
| Power supply problems | The drive may not receive enough power from the Mac, especially with USB hubs or older ports. |
| Disk display settings | macOS may detect the drive but not show it in Finder or on the Desktop due to disabled settings. |
| Corrupted drive | File system errors or disk corruption can prevent macOS from mounting the drive. |
| Unsupported file system | The drive may use a format that macOS cannot fully support, such as NTFS without extra drivers. |
| macOS resource issues | Too many background apps can stop macOS from loading the drive correctly. |
| Physical damage | Internal or external damage from drops, heat, or moisture can stop the drive from mounting. |
As you can see, the problem can range from simple issues like cables or settings to more serious ones such as corruption or physical damage. In most cases, basic checks and built-in macOS tools can help the drive mount again. Next, we will look at practical solutions to fix each cause and get your external hard drive working properly on your Mac.
If your external hard drive will not mount on a Mac and the Mount button is missing in Disk Utility, this is a fairly common issue. It often happens when the drive was previously used on a Windows PC. In this situation, there is no need to worry. A simple and effective solution is to use a reliable third-party NTFS tool such as PartitionAssistant NTFS for Mac.
By default, macOS can read NTFS drives but cannot write to them. Because of this limitation, an NTFS external drive may not mount correctly or may show up as read-only. As a result, you cannot edit, delete, or save files. An NTFS tool removes this restriction and helps macOS work with the drive normally.
After installing the tool, you can mount the external hard drive with one click. It automatically detects NTFS disks and enables full read and write access, allowing you to manage files just like on a Mac-formatted drive. This is especially helpful if you want to avoid reformatting and losing data.
🌟 Note: Please configure Security Policy in iOS Recovery Mode before the process.
Step 1. Open the installed PartitionAssistant NTFS for Mac, then connect your NTFS drive, and the software will automatically mount and display all connected external hard drives on your Mac.
Step 2. Find the NTFS drive you want to write data, and click "Enable Writable". If the status is already Read & Write, simply click “Open” to start using the NTFS external hard drive.
Step 3. You can now copy, move, and delete files without formatting the NTFS drive.
Step 4. After all operations are complete, please click "Eject" to disconnect the external hard drive from your Mac.
If your external hard drive still will not open after trying to mount it, the problem may be caused by file system errors or minor disk damage. macOS includes a built-in repair tool called First Aid that can scan the drive and fix common issues. Running First Aid is a safe and simple step to restore access to the external drive.
Step 1. Connect the external hard drive to your Mac using a stable cable and make sure it is powered on if required.
Step 2. Open Finder, go to Applications, then Utilities, and double-click Disk Utility.
Step 3. In Disk Utility, choose the external hard drive from the list on the left. Click First Aid at the top, then select Run to start the repair process.
Step 4. Wait for the scan to finish and click Done when the process is complete.
After the repair, safely eject the external hard drive and restart your Mac. Then reconnect the drive and check whether it mounts and works normally. If the issue continues, you may need to try other methods to check hardware connections or system settings.
If your external hard drive appears in Disk Utility but you cannot open or use it, the drive may not be mounted properly. In this case, you can try to mount it manually. Although macOS usually mounts drives automatically, manual mounting can help the system recognize the disk and allow access to its data.
Step 1. Open Finder, go to Applications, then Utilities, and launch Disk Utility.
Step 2. Look for your external hard drive in the list on the left and select the one that is not mounted.
Step 3. Click the Mount button at the top of the window to force the drive to mount.
Once the process is complete, check whether the external drive is accessible. If it still does not work, you may need to try other solutions to fix mounting issues on your Mac.
If your external drive still will not mount, reformatting the disk in Disk Utility may help. Formatting resets the drive and fixes issues such as file system conflicts or a damaged partition table. For example, a drive may fail to mount if it uses a format that macOS does not fully support. Reformatting lets you choose a Mac-compatible format, such as APFS or HFS+, so the drive can work properly with your system.
Note: Reformatting will erase all data on the drive. Only continue if you have already backed up your files or recovered the data you need.
Step 1. Connect the external drive to your Mac and open Disk Utility from Applications > Utilities.
Step 2. Select the external drive from the list on the left side.
Step 3. Click the Erase button at the top of the window.
Step 4. Enter a name for the drive, choose a suitable format and scheme, then click Erase to start formatting.
After the process finishes, reconnect the external drive and check whether it mounts normally. If the problem remains, you may need to look into hardware issues or professional repair options.
Mac firmware controls how your system handles hardware during startup. If the firmware settings are incorrect or corrupted, your external hard drive may fail to mount. Resetting the firmware, including NVRAM or PRAM and the SMC, can help restore normal hardware communication.
Step 1. Restart your Mac and immediately press and hold Option, Command, P, and R together. Keep holding the keys until you hear the startup sound for the second time, then release them.
Step 2. Reset the System Management Controller based on your Mac model.
Step 3. If you are using a Mac Pro, Mac mini, or a Mac laptop with a removable battery, shut down the Mac, unplug the power cable, remove the battery, then press and hold the Power button for about five seconds.
Step 4. If you are using a MacBook, MacBook Pro, or MacBook Air with a non-removable battery, shut down the Mac and press and hold Shift, Control, Option, and the Power button together for about ten seconds.
After resetting the firmware, restart your Mac and reconnect the external hard drive. Check whether the drive mounts normally. If the issue continues, you can move on to other fixes related to disk repair or formatting.
If your external hard drive still does not mount on your Mac after you have tried all other fixes, it may be time to seek professional help. Some problems, such as physical damage, firmware errors, or serious file corruption, cannot be solved with home troubleshooting. A professional repair service has the right tools and experience to check the drive and handle these complex issues.
This option can be expensive, so it is important to think about how valuable the data on the drive is before moving forward. If the files are important or cannot be replaced, professional repair may be the best choice.
When selecting a repair service, choose one with a good reputation and positive customer feedback. This helps ensure safer handling of your drive and improves the chances of successful repair or data recovery.
This article shares comprehensive information about how to fix external hard drive won't mount on Mac. This can have many causes, from simple connection issues and power problems to file system errors and physical damage. Fortunately, most of these problems can be resolved using built-in macOS tools, the best disk mounter software for Mac, or by adjusting system settings. For more serious issues, reformatting the drive, resetting firmware, or seeking professional help may be necessary. By following the steps outlined in this guide, you can identify the cause and take the right action to get your external hard drive working properly again, ensuring your data remains safe and accessible.
🗨️ How do I fix my external hard drive not mounting on my Mac?
Start by checking the basics: make sure the USB cable and port are working and the drive is powered on. If it still doesn’t mount, try using Disk Utility to run First Aid or manually mount the drive. If it’s an NTFS drive, use a tool like PartitionAssistant NTFS for Mac to enable full read and write access. In some cases, reformatting the drive or resetting your Mac’s firmware (NVRAM/PRAM and SMC) may solve the problem.
🗨️ Why is my Mac not detecting external storage?
Your Mac may not detect a drive due to a loose or damaged connection, insufficient power, unsupported file system, disk corruption, or macOS resource issues. Sometimes the drive is physically damaged or the ports are faulty. Checking cables, ports, and power, and using Disk Utility to scan the disk usually helps identify the issue.
🗨️ How to force mount an external hard drive on Mac?
Open Disk Utility from Applications > Utilities, select the external drive in the sidebar, and click the Mount button at the top. This forces macOS to recognize the disk. If it doesn’t work, check that the drive is not corrupted and consider using a third-party NTFS tool if the drive is in NTFS format.
🗨️ Why is my external hard drive not being detected?
Common reasons include damaged USB cables, incompatible file systems, corrupted drives, insufficient power, or macOS not recognizing the disk due to system issues. Running First Aid, trying a different port, or connecting the drive to another Mac can help determine the cause.
🗨️ How to mount an unmounted disk on a Mac?
Open Disk Utility, find the unmounted disk in the left panel, and click Mount. If the option is unavailable, run First Aid to repair minor errors. For NTFS drives, use a third-party tool to enable full access. If the disk still won’t mount, check connections, power, or consider reformatting after backing up data.