iMac 27 (Late 2012) Shuts down. #2

Do you still have this problem? I have (had?) a similar symptom where the computer would shut down and it would take a SMC reset to get the computer to re-start. Annoyingly when I took it back to be repaired (twice) the service centre couldn't find anything wrong and I've been trying to work out what is different with my home set-up compared to there's.

My answer to that was that they always used a wired keyboard and mouse when testing my unit and sure enough, if I turn off Bluetooth on the computer and revert back to a wired system the crashing stops.

Do you use a wired keyboard and mouse? If not, are you able to test your computer with a USB rather that Bluetooth set-up.

This doesn't explain why the problem happened but it might at least give you something to work on.

I have the same issue and I also took it twice to the genius bar. They couldn't see it shut down (they kept it just 24h) so they didn't fix it.

Hi !

Same problem here. iMac 27" Late 2012 with 3.4Ghz. 8Gb Ram. Nvidia GTX 680MX. Ramdom shutdows. I can have more then 7-8 in the same day. 4 times in official service but they can't reproduce the problem. ¿?¿?¿?

Thanks!!!

I have had the same problem. I took it into the Genius Bar and they replaced the power supply, which fixed the problem for about a month and now it is shutting down again. This seems to be a somewhat common problem with this version of the iMac. They will probably recommend replacing the logic board next for around $1,000. At that point I may just decide to take my losses on this computer. I'm very frustrated as this is my first Mac and I dropped about $3,500 on a fully loaded machine and it looks like it will only last for about two years. I'm not sure if I am in a hurry to replace it with another Mac.

I have had unexpected shut downs for 3 months. Since December (when the computer was 2 years old aprox.).

As I stated above, after visiting 2 different Genius Bars where they could not fix it, this is what I have accomplished in order to keep using the machine with no shut downs.

I usually had multiple shut downs on a regular day. Sometimes after 2h, sometimes after 7h. When that happened, I needed to unplug the iMac for 15 minutes (I ended up calculating with iOS Timer).

So I though maybe there is a component being charged unexpectedly until the mother board shuts down itself for security. That would explain why changing the Power Supply doesn't work.

Anyway, I decided to connect the iMac to a multiple power socket with a switch. When I'm done working with the iMac, I shut it down and I also switch off the power socket.

Doing that seems to "uncharge" whatever was going on in the iMac as when I come back to turn on both socket and iMac I can work with it for more than 24h.

I've had no shut downs for 3 weeks now. And after having 3-4 shuts downs every day., this is something.

Hello,

have you tried to install 4 memory modules on your iMac? I have exactly the same model and I cannot make it to work with more then 2 modules installed. Please take a look at my thread:

iMac13,2 27" with firmware from 21.5" not seeing the 4 memory bays

This might be slightly off topic but yes, I have my 27" iMac running on 4 modules of 4GB each.

Thank you very much for the answer. You have exactly the same firmware like me which seems to prove that it's not the firmware issue.

At least I will save some time on searching for a different firmware 😉

Same problem. Depending how much time I have it unplugged, more time I can work without shut down.