It is common that Mac fails to mount a hard drive. Many users have been subject to this issue before. It actually can result from many factors. So, this article will expose 5 main causes as well as solutions for this problem.

1. Software To Mount External Hard Drive Machine

Hard drive is the most important part of a computer in that it’s used to store data, supporting computer to work in a normal manner. Therefore, if the internal hard drive is unable to be mounted on Mac system, not only will the system be unable to boot, but also you will be incapable of accessing the drive data. So, this issue is admittedly knotty and annoying. But don’t worry. In the followings, we will unveil its 5 primary reasons and solutions.

Software To Mount External Hard Drive Machine

When you’re planning to use your Seagate drive only for your Mac. There are a few reasons to reformat your drive this way. Reason 1, your Mac can use a Seagate external hard drive formatted as HFS+ for a Time Machine backup. So if anything happens to your Mac you can restore your entire Mac from a Time Machine backup.

Reasons:

1. Virus Attack

Dec 07, 2017  When I plugged in my external hard drive it showed up in my drive in Disk Utility but it was grayed out. I could not mount my hard drives and it would not let me repair, erase, nor partition them, an old and a new one. I decided to click on the view button at the top right corner of my disk utility app and I had 'Show Only Volumes' selected. Jun 19, 2020  Repair external hard drive using Disk Utility: When Mac does not recognize the external hard drive, follow the instructions to ensure external hard drive is recognized on the computer. Navigate to System Preferences Disk Utility; If your external hard drive appears to be in grey, right click on the drive and select Mount. Nov 14, 2019  Most of the time, when you connect an external hard drive to your Mac’s USB port, you soon see it mount on the desktop. Apple likes to ensure these are easy to find, so they also appear in the Finder in the left-hand column under Devices, since Mac’s treat them the same way as another computer.

There may be chances that your Mac system or the hard drive itself is attacked by viruses or malware, causing data corruption like corrupt PST. Hence, your Mac is unable to mount the hard drive. This isn’t rare in that viruses have become more and more sophisticated nowadays.

2. Disk Utility Failures

In addition, this problem may be caused due to Disk Utility faults. As we all know, not only can this tool fix disk issues, but also it can format or partition hard drive. Hence, if you used it to partition drive but failed, then the drive may be unable to be mounted.

3. Catalog File Corruption

Moreover, catalog files are extremely important as it is responsible for storing the record files of partitioned volumes. Therefore, if any catalog file becomes corrupt, Mac will not be able to get the volume information, such as volume size location, description of volume content, etc., thereby failing to mount the drive.

4. File System Damage

File system is responsible for organizing and storing the data in hard drive. Thus, if the drive file system is compromised, the master file table will be impacted in a direct manner. At that time, Mac will definitely fail to mount the disk drive.

5. System Malfunctions

Furthermore, there are likelihoods that the Mac operating system crashes. Hence, the Mac cannot mount your hard drive.

Solutions:

1. Kill Viruses

Based on the first reason above, you need to kill the potential viruses. Launch the anti-virus software on your Mac and then make it scan the disk or the entire Mac to remove viruses.

2. First Aid

“First Aid” is a repair feature in Disk Utility. You can use it to have a try. Insert a Mac OS installation disk and then reboot Mac while holding down the “C” key. In installer menu, select “Disk Utility” and turn to “First Aid” tab. Later, choose the drive and hit “Repair” option.

3. Quit “fsck_hfs” Alike

Many senior users may have noted that as shown in Activity Monitor, a process called “fsck_hfs” or “fsck_exfat” always auto runs on Mac startup. As long as, this process is quitted, the issue will disappear. You can try this solution, too.

4. Reset NVRAM

NVRAM is a small portion of memory used to store some settings for quick access on Mac system. Thereby, you can attempt to reset the NVRAM. Reboot your Mac and hold down the “Command + Option + P + R” key buttons. After resetting, you can retry to mount the drive on Mac.

5. Use Third Party Tool

What’s more, there are multiple utilities that can repair such an issue. Hence, you can download a trustworthy and experienced tool to have a shot.

Author Introduction:

Shirley Zhang is a data recovery expert in DataNumen, Inc., which is the world leader in data recovery technologies, including sql fix and outlook repair software products. For more information visit www.datanumen.com

Summary

When an external hard drive becomes inaccessible or unrecognized on your Mac computer, check it in Disk Utility. If it shows as unmounted, you’ll need to mount the external hard drive and make it recognizable. The best solution is available here for you to follow and fix this issue without losing any data.

The provided solution for fixing unmounted external hard drives can also be applied to fix unmounted USB drive, Thunderbolt drive, firewire drive, etc., on Mac. If you are unable to access or view your external hard drive on Mac desktop, follow-through the following process to make your device accessible without losing any data:

Have you ever met this problem that you tried to open an external hard drive on your Mac computer but the disk displayed as unmounted? If yes, you are in the right place. Here we'll take the unmounted external hard drive as an example to show you how to force the unmounted external hard drive show up on your Mac desktop without losing any data.

You can follow to resolve the same issue on your own now.

Part1. Check External Hard Drive

Before you start to fix the external hard drive unmounted error, you should first check the external hard drive, finding the real cause of the device unmounted error.

Follow through the checking tips here and find out the problem:

# 1. Check the cable

Check if the external hard drive cable is plugged in correctly, not loose. If yes, fasten it. Also, check if the external hard drive is probably plugged in the Mac computer via its connection cable. If not, re-plug the drive and reconnect it to Mac. If it turns out the drive connection cable is damaged, replace one and your problem is resolved.

# 2. Switch USB port

Change a USB port and reconnect the external hard drive. If the external hard drive shows up, congratulations. If not, continue with the next tip.

# 3. Check disk file system

Mac computer can read HFS+, NTFS, FAT32, exFAT, and exFAT. If your external hard drive is another recognizable format, reformat it to a readable file system for Mac.

# 4. Check Disk Utility

• Open Disk Utility by opening new Finder windows > Applications > Utilities > Double-click to bring up Disk Utility.
• Check if the external hard drive is visible.

• If yes, you can simply follow through the next 2 parts to mount your external hard drive and get your data back with ease. If the external hard drive icon doesn't appear below the External section, it means that there might be a problem on your drive. You need to either get a repair or replace it as it might have failed and if it's totally crashed, there's not really much you can do at that point.

Part 2. Mount 'Unmounted' External Hard Drive

Mac Disk Utility is a professional tool that helps resolve most disk management issues on Mac, functioning similarly to Disk Management in Windows OS.

When a storage device becomes unmounted as shown on this page, Disk Utility also assists mounting the device and fixing it back to a healthy state:

Step 1. Open a new Finder window, click 'Application' and open 'Utilities'.

Step 2. Locate and double click 'Disk Utility' to launch it. Locate the external hard drive at the left panel under the External section.

You'll see that the external hard drive is greyed out, marked as untitled. (Untitled means unmounted on Mac computer.)

Step 3. Select the untitled external hard drive and click the 'Mount' button from the Disk Utility bar.

After this, you can restart the Mac computer and reconnect the external hard drive. There, you are good to go and check whether you can access and use the existing data in your external hard drive again.

If not, move to Part 3 and restore all lost and existing data from the external hard drive with ease.

Part 3. Restore Lost Data after Mounting External Hard Drive

Theoretically, if an external hard drive becomes inaccessible after mounting on Mac with Disk Utility, something was wrong with your device. It is caused by the mounting but the device itself.

And the best way is to apply professional Mac hard drive data recovery software to bring your saved data out of the device immediately. EaseUS Data Recovery Wizard for Mac is able to scan and bring all existing data with lost files back from your external hard drive on Mac OS X and macOS systems.

Follow the step-by-step guide below to bring your external hard drive data back:

Step 1. Correctly connect your USB flash drive to your Mac. Launch EaseUS Data Recovery Wizard for Mac. Start selecting the flash drive and click Scan to let the software search lost files on it.

Step 2. After quick scan and deep scan, all files will be presented in the left pane in the scan results.

Step 3. Select files you want to recover and click Recover Now button. Don't save the recoverable files to the USB drive itself in case of data overwriting.

Note: Remember to save your data to another secure location before making sure the external hard drive is secure to store files again.

Bonus Tip: Format External Hard Drive for Mac Compatibility

As we have mentioned, that when the external hard drive file system is unrecognizable on Mac, it may not mount to Mac. Also, if the external hard drive is still inaccessible after mounting, you will need to format the device for Mac compatibility.

Here are the steps:

Step 1. Connect the external hard drive to Mac and open Applications > Utilities > Double-click to launch Disk Utility.

Step 2. Select the external hard drive in Disk Utility and click 'Erase' at the top pane.

Step 3. Set the external hard drive as 'Mac OS Extended (Journaled) next to 'Format'.

Step 4. Rename the drive if you want and click 'Erase' to confirm again.

After this, you can restart the Mac computer and reconnect your external hard drive. Then you should be able to access and save new data on the drive again.

People Also Ask

Some Mac users may still not clear about mounting and unmounting issues on the Mac computer. Here we have collected some frequently asked questions about mounting and unmounting Mac drive and left a brief answer below each question. Find out answers on your own.

1. What does unmounted hard drive mean?

A mounted drive on Mac computer can be directly detected by the operating system and users can directly access saved files on it.

But when a hard drive is unmounted, it will neither be recognized by the Mac operating system or showing up on the computer.

2. Why won't my external hard drive mount on Mac?

There are many reasons that may cause the external hard drive unmounted on Mac. Here is a list of the major causes:

• Hardware and connection issue
• Corrupted disk
• Incorrect formatting of the disk
• Software conflict
• Malfunction of macOS

Based on these reasons, we suggest you back up essential data more regularly. Sometimes, even two copies of essential files are acceptable.

3. How do I mount an unmounted hard drive or external hard drive Mac?

• First, make sure that your external or internal hard drive is correctly connected to your Mac computer.
• Next, reboot the Mac computer and open Disk Utility > locate and select the unmounted drive > Select Mount at the top menu.
• Last, reboot Mac computer again to keep all the changes.

After this, you should be able to access your device and use the saved data again. Download apple tv app mac. If your files are missing on the mounted the drive, EaseUS Data Recovery Wizard for Mac is always ready to help.