# Freezing mac, HDD missing in disk utility



## mcnugget (Oct 7, 2008)

Got an imac 20" A1224, 2.0 ghtz 1GB RAM 250GB HDD - which was randomly freezing and the only way to get back into it was to hold the power button to force a shutdown.
Then during startup, on most occasions the mac would power up displaying the ? box suggesting no HDD or OS. 
So, i assumed the HDD was at fault and have so, replaced it. I also popped in a new 2GB RAM module to be on the safe side.

It was running 10.4 but have installed 10.6 OS and all installed ok and seemed to work fine up until software updates. Now it is randomly freezing again when you do anything from try to open safari to clicking on the apple logo. The beech ball spins and the only way to get back to a working desktop is force the shutdown by holding the button again.

Just booted to the OS install CD and opened up disk utility and began to run a disk verify, ran for about 3-4 mins and found a few errors then the process stopped and failed. It said run a repair. At this point the HDD had disappeared from the device list on the left only showing the DVD drive.

Now it is back to the point where we only see a ? on boot.

Any suggestions? thanks in advance for any help offered


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## Headrush (Feb 9, 2005)

How full was the HD?

Do you have a external HD for testing purposes?
Does it freeze ever time you boot up off DVD?


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## mcnugget (Oct 7, 2008)

was about 100gb free on the old HDD but installed a 1TB HDD to replace it any way. 
Yes got an external HDD, what tests can i perform with this?
just crashed this morning with the grey screen roll over and prompt that the system has to be restarted. This was when trying to erase the HDD in dick utility.

Just going to replace the sata cables now to see if this helps.


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## Headrush (Feb 9, 2005)

mcnugget said:


> Just going to replace the sata cables now to see if this helps.


I'd be extremely surprised if this was the culprit.

I would suggest checking the RAM first if it crashing while booted from the OS X DVD and using Disk Utility.
Depending on how many sticks of RAM you have, you can test each singly as a basic test, or use another computer (Mac or PC) to create a bootable memory test CD. (many Linux distros include one as boot option)


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## mcnugget (Oct 7, 2008)

turns out to be one of the RAM slots. Tested the RAM and its ok. One working slot and every thing is fine now. Thanks for the help though Headrush.


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