Dead iMac Hard Drive Recovery

This is a tale of loss, love but in the end, happiness. My girlfriends 20″ iMac hard drive recently died, although the computer was still under warranty the hard drive could not be easily recovered by ‘MagnumMac’ and if it is replaced under warranty you don’t get to keep the old drive! The hard drive contained the last 3 years photos and Uni work. There was no choice but to pay for a replacement and keep the broken drive. (For anyone who’s iMac starts going slow for a couple of months, then started making a clicking sound, a ‘plonking’ sound and the inability to boot will follow.) These are the steps I used to recover the drive, only loosing about 20 files in 160GB. Note that this drive was VERY dead, it would still spin but would not mount, it had a hardware fault and would ‘plonk’ off if you tried to do so.

  • Put the drive into an external SATA enclosure and connect it to a computer with more free space than the entire drive capacity.
  • Hopefully the disk will mount, if not open /dev directory and try find it. For me it was rdisk3. Now create an image of the disk using dd, from the terminal type:

    dd bs=64k if=/dev/rdisk3 of=/recovered.dmg conv=noerror,sync

    The original post I found used a blocksize of 512, but this was going to take about 25 days to copy using USB, I used 64k which only took about 3 hours. You will end up with a .dmg file.

  • Get DiskWarrior , it REALLY WORKS so I would advise buying it if you have the money. To use DiskWarrior the .dmg must be mounted. As mine wouldn’t mount I had to attach it using the command:

    hdiutil mount -nomount -readwrite /recovered.dmg

  • From DiskWarrior use the “Rebuild” option on the image which will now be in the popup menu. It only takes a minute and will come up with a Report. From the report click “Preview” and it will mount your files as a drive on your desktop. BACKUP YOUR DATA and enjoy!

Websites which made this all possible:


2 thoughts on “Dead iMac Hard Drive Recovery

  1. I’m trying to recover my imac hard drive (1TB) via target mode to another imac that has a external hdd (2TB) but it won’t let me create a .dmg, any suggestions?

    • Hi Alex, I don’t have any experience with target mode but I’ll try.

      First step you need to ensure that the old drive is accessible from the other Mac you are using. On the other Mac open up the terminal, check the last kernel logs with sudo dmesg | tail -n 30 and look at what devices currently connected sudo ls /dev/*.
      Start up the old computer in Target Mode and connect it via Firewire. Re-check the kernel logs and the devices connected to the other Mac. Hopefully you can find a new /dev/rdiskXX or something like that, this is what you should use as the “if=” with the dd command. If you were already using the right device then it might just be matter of running the dd command as sudo.

      Let me know if you have any luck, someone else will probably find it useful too.


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