Disk Utility can fix certain disk problems. But we may get the message "Error: Disk Utility can't repair this disk" when we repair external hard drive on Mac.
When this happens, we are eager to know how we can repair external hard drive. Fortunately, here's the solution to repair external hard drive on Mac when Disk Utility can't repair it.
Guide to repair external hard drive on Mac if Disk Utility can't repair it
If Disk Utility can't repair external hard drive, it means external hard drive not mounted or external hard drive not readable by this Mac computer. We can do nothing but to reformat the drive in most cases. If there's important data in the drive, we'd better recover data from the external hard drive on Mac, and then reformat it.
1st Step: Recover data from external hard drive
iBoysoft Mac Data Recovery is able to recover data from corrupted external hard drive on Mac. It is professional Mac data recovery software that can recover lost documents, photos, videos, music, etc. from Mac hard drives, external hard drives, USB drives, SD cards, memory cards and other storage devices on Mac. It can also recover data from unmountable, unreadable, formatted drives on macOS 10.15/10.14/10.13/10.12 and OS X 10.11/10.10/10.9/10.8/10.7.
Step 1: Download iBoysoft Mac Data Recovery, and install it on Mac computer.
Step 2: Connect the external hard drive to Mac.
Step 3: Launch iBoysoft Mac Data Recovery.
Step 4: Select the external hard drive and click Next button to scan it.
Step 5: Preview the scanning results and choose files need to be recovered, then click Recover button to recover those files from external hard drive on Mac.
2nd Step: Repair external hard drive on Mac
After data recovery from external hard drive, we can repair the external hard drive on Mac by reformatting it with Disk Utility.
Step 1: Launch Disk Utility from Utilities.
Step 2: Select the corrupted external hard drive.
Step 3: Select Erase function, complete the related information (name, format, scheme), then apply.
After finishing those steps successfully, we can repair external hard drive on Mac without data loss when Disk Utility can't repair external hard drive.
When external hard drive not showing up in Disk Utility, please refer to how to fix/repair external hard drive not showing up in Disk Utility.