How to fix a faulty MacBook hard disk

Your Mac hard disk is goosed. You’ve been to the Apple Store and they’ve run some tests and they’ve told you there’s nothing they can do. They suggest you reformat your disk and restore the data from Time Machine… Except you don’t have any backups.

If your Mac boots into its Recovery Partition then you might be in luck.

Here’s a few steps to help you get as much data off a faulty MacBook hard disk. Your level of success with these steps is hard to forecast as it depends on how badly damaged your disk is.

You’ll need

  • your faulty Mac
  • a second “working” Mac
  • a cable to connect the two Macs
  • an external drive
  • a copy of DiskWarrior

Basic Idea

The basic idea is to connect the two Macs via the cable, repair the disk, and copy any retrievable files to the external drive.

The cable

To access your faulty Mac from the working Mac, you'll need a Thunderbolt cable. Your Apple store will sell these. If not try Amazon for a cheaper Belkin option.

If the two Macs are Macbook Pros you could also use a Firewire 800 cable, but check that both Macs have the port before spending the money.

Tip - look after the packaging, because you can return items to both the Apple store and Amazon and get your money back.


DiskWarrior is an excellent piece of software. Its purpose it is to recover as much data as possible. There are no guarantees that it will recover all your data, but its the best on the market for Macs.
Its pricey at US$99, but far cheaper than paying an forensic expert to recover the data. Purchase and download DiskWarrior on to working Mac.

Connecting the two Macs

Switch off both Macs and hook them up using the Thunderbolt cable. Switch on the working Mac and let it boot up into the ready state.
Next we need to boot the faulty Mac into “target disk mode”, which will make the faulty Mac appear as an external drive to the working Mac (it might not visibly appear on the desktop because of the faulty drive issue).
Hold down the ’T’ key on the faulty Mac and power it up. The faulty Mac will boot up into a very basic screen displaying either the Thunderbolt or Firewire logo.

Here’s a Youtube video that shows the process:

Repairing the disk

Its now time to repair the faulty drive using DiskWarrior. Launch DiskWarrior on the working Mac and point it at the faulty drive - which should be visible in the DiskWarrior drop down menu.

Follow the DiskWarrior instructions and let it repair the drive. This process can take up to an hour to complete, depending on the size of the drive and the extent of the damage.

Copying the files

Once DiskWarrior is finished you might end up with an unrecognisable folder structure, e.g. hundreds of folders named “Missing Folder X”. Copy these folders onto an external drive for safekeeping.

Fix your faulty Mac

With your files recovered and stored safely on the external drive, reboot your faulty Mac and let it enter recovery mode.
You should see the option to reinstall OS X.
If you’re not comfortable doing this yourself, go to an Apple store and ask a "Genius" to this for you.

Sift through the Missing Folders

Copy the collection of “Missing Folder X” folders that DiskWarrior recovered from the external drive on to your newly restored “faulty” Mac.

You can either browse through each folder and see if a folder contains meaningful content (photos, documents, etc.) and copy those into your personal folders or you can use Spotlight search and look for (doc, pdf, jpg files). In the Spotlight search results right-click or ctrl-click on a file and choose ‘Open enclosing folder’, which will take you directly into ‘Missing Folder X’ containing the files.


Hopefully you’ll have retrieved most of your data. So now the most important step is to use a sensible modern backup strategy.

Please backup your data. Its affordable and easy to do - read my blog post for an example.

Photo Credit: purplemattfish