[Solved] Disk Utility's First Aid Repairing Process Failed on External Hard Drives

By Molly | Posted to Mac Data Recovery on August 13th, 2018 |

Summary: In this article, we will talk about why Disk Utility's First Aid failed on external hard drives, as well as what to do if First Aid can't repair external hard drives, SD cards, USB drives and more.

Why Disk Utility's First Aid failed on external hard drives?

First Aid in Disk Utility is a small tool designed to verify and fix minor problems of a drive, such as repairing the drive's data structures, fixing external hard drives not mounting on Mac, external hard drives not readable on Mac and so on. However, sometimes Disk Utility failed in verify and repair, or Disk Utility's First Aid can't repair external hard drive problems and states: "The First Aid process has failed. If possible, back up the data on this volume."

Most of the time, First Aid's failure on external hard drives is due to severely corrupted directory of the drive, which was brought about by improper ejection or physical damage.

What to do if Disk Utility's First Aid has failed on external hard drives?

If you have encountered the First Aid failure when trying to fix external hard drives, the simplest way is to reformat the external hard drive. But before that, you'd better back up as many files as possible to another drive, just like Disk Utility suggested.

If backup is not allowed or you have no spare hard drives, you need to recover files from the external hard drive.

Step 1: Recover as much data as possible.

iBoysoft Mac Data Recovery is reliable Mac data recovery software to recover deleted/lost data from external hard drives, unreadable USB drives, Pen drives, corrupted SD cards, memory cards and other external storage devices. It can also recover data from erased/formatted external hard drives, recover data from encrypted APFS external hard drives, etc.

Recover data from external hard drives with iBoysoft Mac Data Recovery

1. Download and install iBoysoft Mac Data Recovery.

2. Launch this program. Select the external hard drive that First Aid failed to repair and click "Next". The program will start scanning this drive for recoverable files.

Recover data from external hard drives

3. After the scanning process finishes, you can click the found files to 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: Erase/reformat the external hard drive.

1. Go to Applications > Utilities > Disk Utility.

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

Erase external hard drive

3. Provide the required details including a name and format to format the drive.

4. Wait until the process finished.

If the external hard drive still doesn't work on Mac, it's probably that the external hard drive has been damaged physically. You have to send it to a local service center or replace it with a new one.


Molly is an editor @iBoysoft who frequently shares useful tutorials about data recovery for Windows and Mac.

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