Late 2012 iMac experiencing total system freezes randomly

[cole01]

I'm not sure what the issue is. Ever since updating to 10.8.4 my system has been going into a deep freeze with the fans running very loudly and the ability to move the mouse but no clicks registering anywhere in OS X. Force quit doesn't work, either by keyboard command or from the Apple menu and the only way to shut down is by holding down the power button.

Everything restarts just fine and there's no evidence of any crash logs or error reports being sent to Apple. Also note that I downgraded to a backup I had of 10.8.3 and yet again, I'm experiencing the same "deep freeze".

It also happens across various applications, most recently while using Activity Monitor.

My specs are:
27" late 2012 iMac
3.4 i7 680MX
16GB RAM
1 TB Fusion Drive
Apple USB SuperDrive usually connected as well

 

[rnb2]

Run hardware diagnostics - boot while holding down the D key, I believe. I experienced similar behavior on my 2009 iMac, and it was a bad DIMM.

 

[cole01]

Run hardware diagnostics - boot while holding down the D key, I believe. I experienced similar behavior on my 2009 iMac, and it was a bad DIMM.

Thank you for your suggestion. I tried to run the extended hardware test twice in a row and it came back with no problems reported.

I suppose I should try a fresh install of OS X now. How do I go about doing this while still being able to restore my files, iTunes, and iPhoto library? I currently have everything backed up on an external with Time Machine.

 

[cole01]

So I reinstalled OS X without having to wipe my drive and yet again, I got another "deep freeze" with the color wheel and complete irresponsiveness. I was using Safari in full screen this time.

Looks like I'll have to bring my machine into the Genius Bar. This is my first time bringing in anything bigger than a laptop so I hope it's do-able. This sucks.

 

[cole01]

Help!

Sorry to bump my thread twice but I figure I'd give you guys an update on my situation in case anyone else is experiencing the same thing...(although from the lack of responses, it doesn't seem so)

Anyway, I decided I'd go ahead and perform a complete clean-install of OS X Mountain Lion since my machine was still suffering from the issue. All was well for a few days, then out of nowhere it happens again. This time on the login screen, not letting me do anything but move the mouse and the fans gradually spinning up to full speed. At this point, I have no idea what's wrong with my machine. I'm thinking it must be a hardware issue.

I guess I'll have to take it to Apple...I'm really reluctant to go to the genius bar with this machine since it's so large (27") and I'll admit I'm not the strongest person around. The one advantage to the GB would be that I took a video as evidence of my iMac doing what I've been describing and then on reboot it happened to go to a circle with a slash above the spinning wheel...Or do you think my best option is to use AppleCare phone service? I'd really rather not be without a computer also since mine has BTO specs and I've heard of Apple replacing iMacs via mail.

I'd appreciate your advice. Thank you so much!

 

[coolerooney]

imac freeze WORKAROUND

Imac 24" mid 2007, mavericks- freezing again after memory increase
did all the "updates"- no succes or "is not required for this computer" message


now "solved" by keeping itunes open, minimalized
not elegant, but works
suspect it keeps the video card busy, so it not falls of its rocks
has not frozen since


Coolerooney

 

[insane79]

my earlier 2007 iMac was giving me the same issues, slow response & identical issue, it turned out to not boot up one day & was a hard drive failure. Best is to run disk utility & do verify hdd there, it will prompt errors if your hdd has issues.

 

[macthefork]

What does the Console log (all messages) show after you reboot when this happens. It should show you what process was hanging and causing the problem just prior to reboot.