Solved: Mac Can’t Repair External Hard Drive
Summary: It could be nightmarish if you have got the below message through Disk Utility while repairing an external hard drive formatted with APFS or HFS. The purpose of this blog is to help you repair corrupt external hard drive on Mac. The blog shares three do-it-yourself methods to fix the drive and recover the data. Data recovery from corrupt external drive is feasible. Free download the software to self-evaluate.
Error: Disk Utility can’t repair this disk. Back up as many of your files as possible, reformat the disk and restore your backed-up files.
The above message doesn’t show up in normal circumstances of external hard disk errors. In most cases, the Disk Utility is vigorous enough to repair an external drive and even your start-up disk. But if the external hard drive is beyond the repair scope of the Disk Utility, then it could be possible that the directory structure of the drive is corrupt severely.
Don’t panic, the below 3 activities could be performed when Disk Utility fails to repair an external hard drive. Further, try Mac external hard drive recovery software as a last resort.
1) Backup External Hard Drive Data
You can try copy and paste all files from the corrupt external or internal hard drive to another destination. But doing this may also result in copying errors to another location. Moreover, the corruption may not allow you to copy & paste all the files from the disk.

2) Fix Mac hard drive using FSCK
You might have luck with FSCK command line.
To run fsck command you have to restart Mac and log in as ADMIN. Launch Terminal, enter df -h1 and press Return. Use of df-h1 will let you know the path of the internal disk drive.
Use below line
sudo fsck_hfs -r -d /dev/disk1s1
The command (-r) in the above code will recreate Catalog B – Tree. It will help you fix Invalid B-tree node problem occurred on the disk drive. It will further resolve errors like –
- Invalid count
- Invalid key length
- Invalid volume file count
- Invalid volume directory count
- Invalid volume free block count, and likewise.
3) Recover External Drive using Stellar Data Recovery Professional for Mac
Though helpful, FSCK isn’t the sure shot method to repair the corrupt external/internal hard drive. You might need the help of a professional external hard drive recovery software for Mac. Stellar Data Recovery Professional is a sophisticated application to scan and recover your APFS or HFS drive.
Step 1) Connect your external drive and launch Stellar Data Recovery Professional on your Mac. Customize your scan as shown below.

Step 2) Select your external hard drive and toggle on Deep Scan feature. The deep scan feature scans all the sectors of the external hard drive to bring back lost data. Otherwise, stick with Quick Scan to recover the file-structure. Press the Scan button.


Step 3) After the external hard drive scans complete, navigate through the Classic list, File or Deleted List to view and preview your files.

Step 4) If you have activated the Stellar Data Recovery Professional for Mac then you will be able to recover or save your files conveniently.

Video Tutorial – Mac External Hard Drive Recovery
Conclusion
Not just the corrupt HFS drive or volume but you can leverage & activate Stellar Data Recovery Professional for Mac to image an APFS external hard drive for the purpose of data recovery.
The process to do the job will be the same as mentioned in the sequential steps and the video tutorial.
Can Stellar Volume Repair speed up my MacBook Pro 2012?
Hi James,
Thanks for writing to us!!!
Definitely, if your Mac startup disk is slowing down due to corruption, bad disk permissions or damaged directory structure then Stellar Volume Repair will repair the damages and re-create the directory structure. This will surely optimize and improve the performance of your MacBook Pro. I also recommend you run Stellar Speedup Mac utility to clean up your Mac hard drive and maintain at-most 15% of free spaces. Here, you can avail both the software at discounted price – Register Stellar Drive ToolBox.
Hope this helps!!
Vishal
the fsck -r -d worked great! Thanks for a really helpful article.
I am writing in the midst of a blunder where I have accidentally restored OS X Yosemite DMG file to my WD external hard drive formatted with HFS+ partition scheme. Now my WD hard drive partitions aren’t mounting on Disk Utility. Is there any way to get back partitions and fix the file structure that got damaged?
Hi Gillock, not just the hard drive needs to get repaired but your data also requires recovery. I recommend you register Stellar Mac Data Recovery Platinum Edition to recover files from the hard drive and then repair it with Volume Optmizer application which is included in the Edition.
I am trying to create a USB disk to boot my old iMac whose drive is bad but the USB is freezing and not taking me beyond loading so that I can access my iMac hard drive. Any recommendations?
Kathy, may be because the bootable USB isn’t prepared correctly. You may order Stellar Volume Repair with a bootable USB support which will boot up your Mac OS X and repair the corruption on the Macintosh HDD.
Hi,
My 2-years old Mac crashed suddenly and only window I can be able to see in my Mac is OS X Utilities with 4 different options. I already know that I have to pick “Disk Utility”. So I did. I select “Macintosh HD” (it’s grey) from left side and hit “Repair Disk” (“Verify Disk Permissions” and “Repair Disk Permissions” are grey) and got the error: “Error: Disk Utility can’t repair this disk. Back up as many of your files as possible, reformat the drive, and restore your backed-up files.” How can I back up my files? Please help me!
Mac OS X Yosemite
I recommend you to take the backup of your hard drive and then fix your hard drive using the help of FSCK command. If the FSCK command is unable to correct it, then fix the drive with the help of Stellar Volume Repair Software. It will rebuild the corrupt directory structure and also bring your data back.
Can Volume Repair rebuild NTFS drive?
No. Stellar Volume Repair software supports HFS, HFS+ formatted hard disk drives.
Do you have this software available for Windows? I have Toshiba NTFS formatted drive which is not showing up on my Windows 10 machine. How should I repair it?
Hello Craig,
Unfortunately, Stellar Volume Repair works only for Mac OS X (HFS). We recommend you do some search for a similar product that can repair your NTFS formatted drive.
Hi Vishal,
My disk utility is failing to repair disk permissions on my Mac Pro. Will Stellar Volume Repair fix this issue without registration?
Regards Paul.
Hello Mr. Paul,
Yes, Stellar Volume Repair will fix your bad disk permissions without registration. However, in order to repair damaged directory structure or Invalid B tree node error you need to activate it.
Regards
Vishal
Hi Josh, Sorry for the late reply.
Stellar Partition Manager isn’t a repair software. It creates, resizes, deleted, hide & reveal partitions on Macintosh HD. In order to repair your hard drive you need to download Stellar Volume Repair.
Hope this helps!!!
I have downloaded Stellar Partition Manager on my MacBook Pro system but how should I repair my partition with this tool?