Q&A: Dead Mac recovery

Q My husband was still using my ancient G3/G4 tower when it froze, apparently dead. It refuses to start up now. How can we recover what is left on its hard disk?

A Sometimes even apparently dead Macs can spring back into life from a bootable external drive.

However salvaging the files from a probably dead hard disk is best performed without further messing. With the mains supply securely turned off, but grounding yourself carefully, open the case and remove its hard disk.

Place it inside a parallel ATA external drive enclosure with a USB interface, and hook that up to your modern Mac. Current disk repair and recovery utilities should still be effective tools to salvage its contents.

Comments If the files on the drive are particularly important but you cannot justify (or afford) the cost of a data recovery service, a good plan is to connect a second, freshly formatted blank external hard drive of at least the same size. Then using a disk tool such as SuperDuper or Carbon Copy Cloner (or dd from the command line) perform a block-by-block mirror copy from the sick hard drive to the blank drive.

If you want to try the wizard’s trick using the shell command dd for a block copy, the form of command to use runs something like
dd bs=512 if=/dev/rdisk#1 of=/dev/rdisk#2 conv=noerror,sync
where rdisk#1 is the device name of the sick drive, and rdisk#2 is that of the new drive on which you wish to create the copy. Further details are displayed by typing man dd at the command line in Terminal.

Once that is complete, eject the original sick drive, and put it away for safe keeping. Then any repairs that you make are to its copy, and the original remains unaltered.

When you have covered as much as you want from that external hard drive, you could then repair or re-install the version of OS X on it ready to try to reboot the old G3/G4 tower, perhaps.

Updated from the original, which was first published in MacUser volume 30 issue 04, 2014.