How to Run First Aid to Repair the Problematical Disk on Your Mac?

By Anna | Posted to Home > Howto on November 19th, 2020 |

Summary: This content is about Disk Utility First Aid on your Mac. It includes how to use First Aid, how to run First Aid from macOS Recovery mode, and what to do if Disk Utility First Aid fails or is not working on your Mac.

Disk Utility First Aid is a built-in disk repair software in macOS. Its main task is to verify and check the health of the disks and volumes on your Mac, such as Macintosh HD, SSD, external hard drives, USB drives, flash drives, and SD cards.

If necessary, First Aid is able to repair minor errors in disk file system and partition structure, which cuts the loss before the disk gets more serious corruption.

How to run First Aid to repair the disk on your Mac?

When your Macintosh HD and external drives are not working, unreadable, corrupted, or unmountable, or your Mac won't turn on, you can use First Aid to check if there is a problem inside the disk.

Step 1: Open Finder, go to the Applications folder, Utilities folder, find Disk Utility and open it.

If the problematical disk is Macintosh HD, you need to repair it after booting into macOS recovery mode :

boot into macOS Recovery mode

How to Boot into & Use M1 Mac Recovery Mode

Then you can select Disk Utility from macOS Utilities window and click Continue.

Disk Utilities in macOS Recovery mode

Step 2: Click on View and choose Show All Devices to list all detected disks and volumes.

Step 3: Select the drive or volume that you want to repair in the left sidebar.

Step 4: Click First Aid on the top menu of Disk Utility.

Step 5: Click Run to check and repair errors in this drive.

If Disk Utility reports that the operation successful or has been repaired, you're done. Check if you can access that disk.

First Aid succeeded

If Disk Utility First Aid process has failed, you can expand "Show Details" and see the detailed error code and message as below:

After Disk Utility can't repair the disk, it's asking if possible back up the data on this volume.

First Aid failed to repair the disk

Disk Utility First Aid failed to repair the disk, what to do?

If you receive a report that Disk Utility First Aid process has failed or Disk Utility First Aid can't repair the found errors, you'd better back up your data as much as possible. There are several solutions you can have a try to back up the data:

1. Back up the data with macOS built-in Time Machine.

2. Recover data with iBoysoft Data Recovery for Mac.

3. A local data recovery specialist.

After backing up the data, you can erase this drive with Disk Utility and make the external drive working again, or reinstall macOS on the Macintosh HD.