Solved: Restore Data from Unmounted External Hard Drive on Mac

Tracy King updated on Jan 21, 2019 to Mac File Recovery | How-to Articles


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.

Can't access data on an unmounted external hard drive

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 solve the 'external hard drive unmounted' issue on Mac computer, we'll divide all the operations into two parts. You can follow to resolve the same issue on your own now.

Part 1. 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, Disk Utility also assists mounting and fixing the device back to a healthy state:

  • Step 1: Launch Disk Utility, check external hard drive at the left panel.
  • You'll see that the external hard drive is greyed out, marked as untitled.
  • (Untitled means unmounted on Mac computer.)
  • Unmount external hard drive.
  • Step 2: Select the untitled external hard drive and click the "Mount" button from the Disk Utility bar.
  • Unmount external hard drive and make it recognizable.

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

If not, move to Part 2 and restore all lost and existing data from the external hard drive.

Part 2. Restore lost data from external hard drive

An efficient way to recover data from the external hard drive after mounting it using Disk Utility is to apply professional Mac hard drive data recovery software for help.

Here you can try EaseUS Data Recovery Wizard for Mac which fully supports all Mac OS X and macOS systems. You can directly download this software on Mac computer, scan and restore all data:

If your data on the device is less than 2GB, EaseUS Data Recovery Wizard can be your best choice.
By sharing the scanning result to your social media account such as Facebook, you can get 2GB recovery capacity for free.

If you are using the current recommended version, when the scanning process completes, you can preview all found files, then activate it to restore all lost data.

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.

select the flash drive where data lost and click scan

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

scan lost data on the flash drive

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.

click recover now button to recover lost flash drive data on your Mac

Extra Tip

After fixing the external hard drive not mounted issue, it's also necessary to find out how did your device become unmounted.
The reason why storage devices become unmounted are various, and here is a list for you to check:

  • Disk utility failure
  • File system corruption
  • 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. Of course, EaseUS Data Recovery Wizard for Mac is also a great choice when you lost data on Mac or your storage devices.


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Frequently Asked Questions

1. Why choose EaseUS Data Recovery Wizard?

"EaseUS Data Recovery Wizard is the best we've seen. It's far from perfect, partly because today's advanced disk technology makes data-recovery more difficult than it was with the simpler technology of the past, but it's fast and efficient..."PCMag

"The first thing you'll notice about EaseUS Data Recovery Wizard Pro is that its interface is very clear and uncluttered, with only a small collection of self-explanatory controls. You won't find lots of extra options hidden in a system of hidden menus, either; what you see really is what you get."techradar

"Recover lost files, even after deleting a partition or formatting your drive."Macworld

2. Why cannot I recover 2GB data for free?

It is recommended to check the version installed is Free or Trial because they are different versions.

Trial has data preview function but cannot save any files, while the Free version enables to recover 2 GB files. The default free space is 500 MB and you may share the product on social media to get another 1.5 GB.

3. Why cannot the recovered files be opened?

A file is saved as 2 parts on the storage device: directory info (which is comprised by file name, time stamp and size info, etc.) and data content.

If the files with original file names and folder structures cannot be opened, one possible reason is the corrupted directory info. There is still a chance to recover the data content with the RAW Recovery method in our software.

4. Why isn't it suggested to recover the files back to the original drive?

The storage structure of the lost files would be altered or damaged by any changes on the drive. If you save the recovered files back to the same drive, the original data structures and data content would be corrupted or overwritten, which causes permanent data loss. So you should prepare another disk to save the files.

5. How can I check whether my data is recoverable or not before purchase?

The Free version helps you save 2GB files, so verify the recovery quality of our product before purchase.

6. How long does it take to scan the drive?

It strongly depends on the capacity of your hard drive and the performance of your computer. As reference,most drive recoveries can be completed in around 10 to 12 hours for a 1-TB healthy hard drive in general conditions.

About Data Recovery Wizard

It's super easy to recover 250+ types of files after deletion, disk formatting and virus infection. Click the links and compare the difference of each version.