Fix external hard drive not showing up/recognized/detected in macOS Catalina/Mojave/High Sierra

Posted by Katrina to Mac Data Recovery on June 13th, 2018

Summary: The external hard drive not showing up/recognized/detected in macOS Catalina/Mojave/High Sierra is one of the most frequently asked questions recently. This article will tell you how to fix the this issue and recover data from the not showing up external hard drives/USB drives/SD cards with iBoysoft Mac Data Recovery.

Normally, when you insert an external hard drive in your Mac computer, it soon appears on the desktop or in the left-hand column under Devices. However, sometimes your Mac doesn't recognize the external hard drive, or the drive fails to show up in Disk Utility/Finder. It's so annoying because if the external hard drive doesn't show up on Mac, you can't access files stored on it and the files may be corrupted.

There are numbers of reasons why your Mac won't recognize a drive. It can be faulty cables, it may have been formatted incorrectly, it may be corrupted or there could be something else. Now follow the methods below to troubleshoot the external hard drive not showing up/recognized/detected in macOS Catalina/Mojave/High Sierra error without data loss.

Method 1: Do some basic checks

When your external hard drive is not recognized/detected by Mac, the first thing is to do some basic checks as below.

1. Make sure the external hard drive is properly plugged in, not wobbly or loose. It sounds obvious that if the drive is not connected properly then it won't appear on your desktop.
2. Reboot your Mac computer. Sometimes, the disk won't boot due to macOS issue. Hopefully, restarting your Mac computer will clears your macOS's memory and fix some data damage. Choose the Apple menu > Restart. Or press and hold the power button. When a dialog box appears, click the restart.
3. Try using a different USB cable to ensure that it is not at fault. If it's plugged in correctly, the cable could be at fault.
4. Try another computer. You can confirm whether or not the drive is faulty by trying to connect it to another computer if you have a one.
5. Try a different port or plug another device in to see if the port works. It could be a hardware issue with the Mac.

Method 2: Check if the external hard drive is formatted for Mac

In general, if the external hard drive is in Windows NTFS format, your external hard drive will be recognized by macOS Mojave and show up in Disk Utility. However, you can only read the files but can't edit. To make , you can connect the external hard drive to a PC or check it in Disk Utility directly. If the external hard drive is in NTFS format, here are the solutions.

Option 1: Reformat the external hard drive to a file system that Mac can read and write to, such as APFS, HFS+, HFS, exFAT, etc. Before that, please back up the files on the external hard drive.

Option 2: Install a professional NTFS for Mac program on your Mac to help you write to NTFS drives without hassle.

Method 3: Check the /Volumes/ folder

Most of time, your Mac computer will show all connected and mounted volumes in the /Volume/folder. You can check the folder whether the drive is there.

Launch Finder and in the menu bar, click Go > Go to folder. Then type /Volume/ and hit Enter. Then you can see a folder that shows all mounted drives and disk images. If your external hard drive is listed here, please try to access it.

Method 4: Show external hard drives on the desktop or in Finder

If your Mac isn't set to show external disks in Finder or desktop, the external hard drive you inserted will not show up in macOS 10.14 Mojave or earlier.

Option 1: Show the external hard drive on the desk top. Go to Finder > Preferences > General tab and select "External disks" to make external hard drives show on the desktop.

Show external hard drive on the desktop

Option 2: Show external hard drives in Finder. Go to Finder > Preferences > Sidebar and make sure the "External disks" under "Locations" is ticked. Then your external hard drive will appear in Finder.

Show external hard drive in Finder

Method 5: Update macOS

Sometimes, it will help when your external hard drive isn't showing up. Try applying macOS updates, especially some firmware updates relate specially to peripherals and devices that connected via USB.

To update macOS, launch the Mac App Store and click Update tab on the top.

Method 6: Check whether the external hard drive can be found in Disk Utility

To make sure whether your external hard drive is detected by Macs, you can go to Applications > Utilities > Disk Utility and check if the external hard drive is showing up in the left-side list.

Scenario 1: The external hard drive shows up in Disk Utility.

If the external hard drive shows up in Disk Utility, that means your external hard drive isn't mounted but has already detected by your Mac.

a. Mount the external hard drive manually.

If the icon of the external hard drive is grayed out, it means the drive is unmounted. You are able to manually mount the external hard drive.

Step 1: Open Disk Utility.

Step 2: Right-click the external hard drive from the left sidebar and then click the Mount button.

b. Repair the unmountable external hard drive via First Aid.

If the Mount option is grayed out, the next choice here are First Aid. First Aid will check the disk for errors and the repair the disk if necessary.

Step 1: Launch Disk Utility.

Step 2: Choose the grayed out external hard drive from the left sidebar.

Step 3: Click the 'First Aid' tab on the top.

Repair unmountable external hard drives via First Aid

c. Reformat the external hard drive that isn't showing up in macOS Mojave.

If First Aid failed to repair the external hard drive that didn't show up in macOS Mojave, the file system of the drive may be seriously corrupted. So, you have to reformat it to make it re-usable.

But, reformatting will clean all data stored on the external hard drive. If you don't have any backup and don't want to lose the data, you need to recover data from the unmountable external hard drive with professional macOS 10.14 Mojave data recovery software, such as iBoysoft Mac Data Recovery.

iBoysoft Mac Data Recovery is one of the best data recovery software that can recover deleted/lost files from emptied Mac Trash, recover data from formatted, inaccessible, corrupted, unmounted, unreadable drives, including hard drives, external hard drives, USB flash drives, memory cards, SD cards, etc. It's fully compatible with macOS 10.15/10.14/10.13/10.12 and Mac OS X 10.11/10.10/10.9/10.8/10.7.

Whatever you are a newbie or experienced user, you can apply iBoysoft Data Recovery without any difficulty. With only three steps, you can get all lost data back. It allows you to preview all recoverable files, including documents, photos, music files, videos, emails, etc. Besides, iBoysoft Data Recovery also offers you many filtering and sorting options, which helps you to focus on the right content from a mass of scanning results.

1. Download and install iBoysoft Mac Data Recovery on Mac.

2. Launch iBoysoft Mac Data Recovery.

Recover data from not showing up external hard drive in macOS Mojave

3. Select the unmountable external hard drive and click "Next" button to scan for all the lost data.

4. Preview the searching results, choose files you need, and click "Recover" to get them back.

5. Launch Disk Utility.

6. Select the external hard drive from the left sidebar of the window.

7. Click the Erase button on the top of the Disk Utility window.

8. Complete the related information (name, format, scheme), then click Erase.

Ideally, your external hard drive can show up in macOS Catalina/Mojave/High Sierra now.

Scenario 2: The external hard drive doesn't show up in Disk Utility.

If the external hard drive doesn't show up in Disk Utility, it's possible that the drive have encountered any hardware issues. Move to method 6 to make sure of that.

Method 7: Run Mac diagnostics to detect hardware issues

Apple Service Diagnostic is a set of diagnostic tools used by technicians to find faults. You can use it to confirm or deny your suspicions. If the external hard drive has been physically damaged, you have to send it to local disk repair center.

Step 1: It is advised to disconnect all the external devices except keyboard, mouse and other useful devices.

Step 2: Reboot your mac or you can power on your mac if is power off.

Step 3: Press and hold D button on your keyboard. Hold the button until you would asked to choose language.

Step 4: After selecting your language, it will display a progress bar stating "checking your mac".

Step 5: After completing the diagnostics, it will suggest you the solutions for the errors diagnosed.

Method 8: Reset your Mac's NVRAM

NVRAM is helpful to retain the information while power is turn off. If you experience issues related to these setting or others, resetting NVRAM might help.

NVRAM is helpful to retain the information while power is turn off. If you experience issues related to these setting or others, resetting NVRAM might help.

Step 1: Shut down or Reboot your mac.

Step 2: Immediately press these four keys in a sequence i.e. command, option, P and R.

Step 3: Hold the keys for at least 20 seconds and after you hear the second chime, release the buttons.

Step 4: After releasing the keys, your mac will restart and hopefully your drive will show up.

To sum up

There are lots of potential solutions for an external hard drive not showing up/recognized/detected in macOS Catalina/Mojave/High Sierra. No matter what happens, the first and foremost thing is to retrieve all important data back, iBoysoft Mac Data Recovery could be your best assistant.

To prevent an external hard drive not showing up issue, it's advised to properly eject or connect your external drives at any time. In addition, always backup critical files on another drives of in the cloud.

Still have questions?