how to Hardware Test imac 2008

The Apple Hardware Test is located on disc two of the original software install discs. The discs are model specific so you need either the discs that shipped with the iMac or a set from another 2008 iMac. You may be able to find a set on ebay or possibly find the correct test software here https://github.com/upekkha/AppleHardwareTest

Allan Jones wrote:

Ad me to those who were never able to make downloaded versions of AHT work, even when Apple hosted the downloads.

If you erase a USB stick (or even a USB drive) as GUID partition and MacOS Extended (Journaled) it should be possible to just use Disk Utility to "Restore" the image to the volume on the USB stick. Usually you first need to run an image check or ASR (check image for restore maybe? It is available on one of the menus in Disk Utility and Disk Utility will tell you it needs to be run when Restoring the image). The README contained within the .dmg files should have these instructions. I know the Github repository has other instructions involving the command line, but they should not be needed.

Macs can be very picky about the USB sticks used for booting. Plus the 2010+ Macs have newer firmware which may prevent the older diagnostic images from working/booting. I'm not sure about the 2009 and earlier Macs. It is unfortunate Apple breaks things and never bothers to fix them.

Good call.

Hours ago, my mac browser froze; with a larger reply with the github and other links attached.

The only way out, after half-hour, was to Force Quit. Then, booted into recovery partition; with

unmounted drives, was able to repair. Spent a few extra hours with a major detour; not a thing

I did or had ready, could be saved. (Nothing here ever has; after force-quit/restart, actually!)

Sorry for your bad luck 😟 I wasn't aware of other links for AHT software.

Ad me to those who were never able to make downloaded versions of AHT work, even when Apple hosted the downloads.