Q&A: Accessing the hard drive in a broken iMac

Q We have a mixture of old and new iMacs. One of the old iMacs will not start up because the display malfunctions, implying a graphics adaptor failure. How can we recover documents from its disk?

A The simplest solution, if the broken iMac has a FireWire port and a working iMac has one available too, is to boot the broken iMac in FireWire Target mode.

Locate a good quality FireWire cable with the appropriate plugs: these could be older 6-pin FireWire 400 or the newer rectangular FireWire 800 version. With the broken iMac powered off, connect the iMacs using the cable. Then start the broken iMac up whilst holding the T key down on its keyboard until you think you can see a FireWire or T icon on its screen.

Cross your fingers, and its hard disk should mount on the newer iMac. When finished, remember to eject the old iMac’s disk properly.

If that does not work, it suggests more extensive problems in the broken iMac, and your best bet is to shut it down, disconnect from the mains, and open its case. Use Apple’s manual, found through here, or iFixit’s guide from here, to remove its hard disk and install it in an external USB drive enclosure, for connection to a working iMac.

Updated from the original, which was first published in MacUser volume 26 issue 25, 2010.