Mac Data Recovery

Solved: Mac Can’t Repair External Hard Drive

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    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.

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    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.

    Professional - Select the Location

    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


    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.

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    About The Author

    Vishal linkdin

    Vishal is a data recovery expert @Stellar. He addresses data loss scenarios on a Mac. He intends to help people solve their macOS problems. Besides, Vishal prefers to read about astronomy and autobiography, and his favorite is Steve Jobs - The man who thought different written by Karen Bluementhal.


    1. Hello,
      I am trying to repair an already malfunctioning startup drive on my 2014 macbook pro on 10.9 osx mavericks. I have a secondary macbook pro of a similar year with the same OS. however the stellar repair software says that it can only make a bootable usb of the startup drive of my secondary computer. Can I still use such a usb to repair my first macbook pro?

      1. Hi Leonard,

        Thank you for contacting Stellar Data Recovery.

        Stellar Volume Repair does repair volume errors and damaged directory.

        We recommend you to try the demo version of the software to check the possibility of repair for your volume.​
        Link: [DMG Removed since Stellar Volume Repair is discontinued] Read More

        Please feel free to get back to us for any further query.

        1. Hello Vishal,
          I downloaded the demo version of the software but I was not able to create a bootable USB until I paid for the registration key? Is this normal? Anyway, I did not realize that I had to create the bootable USB on a computer with the SAME EXACT operating system as on my computer. Your web site says “same configuration” but does not explain exactly what that means. Therefore, I used my friend’s iMac (running OS X 10.13.3) to open the software and created the bootable USB. Of course, my computer (set up with OS X 10.6.8) would not boot from the USB. I called tech support this morning and they explained to me that I needed to create another bootable USB on another iMac with OS X 10.6. Again, I did not realize that before I already used the one-time-use-only registration key. The supervisor (Ronit or Ronid) who assisted me told me that he would send an email with a new regisration key. Later, another tech support person (Amit) sent me a follow-up email with instructions to create a new bootable USB but did not include a new registration key. Please understand that my HDD has the “Invalid catalog PEOF” error, therefore I cannot boot up my system in order to load your software directly to it. The only way that I can use your software is to load it onto another computer and create the bootable USB to then use in my computer to analyze and repair my HDD. If I am able to find another iMac with OS X 10.6 then I will need a new registration key as I explained during my tech support call this morning. If I am unable to find another iMac with OS X 10.6 then are there any other options to receive a bootable USB that will work on my computer? Keep in mind that I have already paid for the software.

        2. Hello Leonard,

          We would like to inform you that demo version of Stellar Volume Repair does not allow to create a bootable USB.

          Once the software has been purchased then bootable USB can be created for repairing the boot volume of a mac system. As your system is not booting up so you need to create a bootable USB on another Mac with the same configuration.

          In case you are unable to find another iMac with OS X 10.6 then unfortunately bootable USB cannot be created. However you can use Stellar Mac Data Recovery software if you wish to recover the data from your Mac system.

          Please feel free to get back to us for any further query

      1. Hi Carlose,

        If you are asking to repair a corrupt HFS external drive then yes you don’t need to create a bootable USB. Is that what you are trying to say?

    2. Hey! Third time this year my MacBook has crashed and each time the apple service guys completely rebooted my device with new software and none of times it could sav any of my data. Today it’s happened again. My MacBook starts and half way through it shuts down on its own. And I did the fsck thing and it said the volume Macintosh HD could not be repaired. Can you please guide me? Thanks

      1. Hey Shika,

        Did every time your hard drive was changed? If no, then your device must be failing. I can recommend you a couple of things.

        1) For logical damages: try Stellar Volume Repair tool to rebuild and repair corrupt Macintosh HD directory structure.

        2) For physical damages: replace the HDD.

    3. I have launched the Stellar Volume Repair, it’s been running the verification mode for the last 3 hours. How long will that whole process including repair take? Approximately. It’s 250GB disk.


    4. Disk utility gives me this error

      “Rebuilding catalog B-tree
      The volume Macintosh HD could not be repaired.
      Volume repair complete.
      Updating boot support partitions for volume as required.
      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.”

      I am much concerned with the the volume macintosh hd could not be repaired. Please provide some help.

      iMac 2015
      2 TB Internal Hard Drive
      8 GB RAM
      macOS Sierra 10.12.2

      1. Hey Ted,

        Your hard drive is corrupt and needs to get repaired using professional software. Try Stellar Volume Repair for macOS Sierra to create a bootable USB for repairing corrupt startup disk i.e. Macintosh HD. It will resolve the problem of The volume Macintosh HD could not be repaired.


    5. Mac hard drive cannot be repaired with It’s failing fast throwing catalog errors which I am unable to understand fully? How rebuilding catalog b-tree on Macintosh HD is done?

    6. As of now i am in office, but the error says: Disk Utility cant repair it. Backup as many files as you can. and there was an error number as well.

      1. Thanks for the information Virendra.

        I would like to inform you that Stellar Volume Repair is not yet compatible with the macOS sierra 10.12.


        1. Then How come my interal SSD and bootcamp partition are visible in Volume Repair if it is not compatible?

        2. Hello Virendra,

          Is your external hard drive showing up in the Disk Utility (even as unmounted)?

      1. Hello Virendra,

        What version of OSX you are running and is your external hard drive password protected. Also, let us know the model of your ex-hdd.


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