[Solved] External hard drive won't mount on Mojave/High Sierra

Posted by Katrina to Mac Data Recovery on January 4th, 2018

External hard drives are widely used to add more hard drive storage space or to back up your important files. However, lots of users post that they can't mount their Seagate, WD, Toshiba or Samsung external hard drives on macOS Mojave/High Sierra. An external hard drive won't mount, how to fix? This passage will show you the right answer.

External hard drive won't mount on Mac, how to fix?

Unable to mount an external hard drive on Mac? It is because the drive is damaged for some unknown reasons that the system fails to recognize it. Even so, here are still some effective solutions to fix external hard drive not mounting/showing up issue. Just follow the steps below:

Fix 1: Repair unmountable external hard drive with Disk Utility

Fortunately, Mac has built-in repair tool which can check the minor error on disks. It is named as First Aid, and you can run it whenever you face any problem on disks.

Step 1: Launch Disk Utility.

Step 2: Choose the unmounted external hard drive.

Step 3: Select First Aid in the top center and click Run.

Repair unmountable external hard drives via First Aid

Fix 2: Reformat to fix external hard drive not mounting on Mac

If Disk Utility cannot repair your unmountable external hard drive, the external hard drive may be seriously corrupted. Don't worry, as long as the unmountable issue isn't caused by hardware problems, it can be fixed by reformatting. But reformatting will remove all data stored on the external hard drive. If you have useful data on the drive, please recover data from unmountable external hard drive at first.

Step 1: Recover data from external hard drive on Mac

As the best free Mac data recovery, iBoysoft Mac Data Recovery is able to recover from unmountable, unreadable, corrupted, inaccessible external hard drive, hard drive, USB flash drive, SD card, memory card, etc. It supports recovering documents, videos, music files, pictures, emails on macOS Mojave 10.14/High Sierra 10.13/Sierra 10.12/10.11/10.10/10.9/10.8/10.7.

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

2. Launch this program. Select the unmountable external hard drive and click "Next". The program will start scanning this drive for recoverable files.

Recover data from unmountable external hard drive with iBoysoft Mac Data Recovery

3. During or after the scanning process, you can click the found files and preview.

4. Choose what you want to get back and click "Recover".

5. Go through the recovered files and make sure all desired files are back.

Step 2: Fix external hard drive not mounting on Mac by reformatting

1. Go to Applications > Utilities > Disk Utility.

2. Select the unmountable external hard drive and click "Erase" on the top.

3. Provide a name and a format to erase the drive.

When finished, you can mount your external hard drive on Mac and use it again.

Final thoughts

It's desperate to suffer from an unmountable external hard drive with inaccessible contents. Thankfully, there is still a hope to fix it without data loss. With the assistant of iBoysoft Mac Data Recovery, no matter the unmountable issue is caused by system crashes, virus attack, software failures, etc, you are able to get lost back.

Still have questions?