Why is my imac shutting down by itself?

Hello again,

Bringing updates on my case. So, since the iMac shut down while they were running the apple tests at the tech support place, they were able to make the warranty work. After two more days apple sent the logic board for replacement. Its been a week since they changed it and everything seems to be alright now, I haven't had any problems so far.

I hope you are all solving your problems as well, cuz this issue is in fact very annoying and stressing.

Hi Jay, that is not much RAM. Are you watching Activity Monitor to see what is happening? Cheers Bryce

…Does this help or assist? http://9to5mac.com/2013/08/16/apple-opens-graphics-card-replacement-program-for- some-mid-2011-imacs/

Thanks for the info.

Unfortunately, my iMac misses out by a few months - late 2012 with newer (and supposedly?) trouble free graphics card (NVIDIA GEFORCE GTX 675MX).

Finally have a booking with a local genius bar - we shall see.. Still, big hassle getting this large machine in, and I'll probably have to pay $$$ 😟

I tried the fan suggestion and it seemed to work for three days, putting the unit under intense graphic use. On the third day, it shut off again. Sign.

I've reading this intently. We have several different machines here, with possibly different problems.

1. Power supply. This is a problem that has been well noted for years; a computer will simply turn off, apparently at random. This happens with computers that are usually a few years old, but the pattern doesn't change: your computer randomly turns off. If you use the affected computer quickly, the time until the next "turn off" gets less and less. If you give the power supply longer to recover, the interval will be longer.

2. Heat. You can't run a computer without production of heat, but heat should be minimized whenever possible. That's why applications like HD Fan Control are so popular; they extend the life of your computer by allowing more air circulation.

3. RAM. If you use incorrect RAM, a computer may experience sudden power loss or sleep. If this happens relatively frequently, this deserves special consideration. This can be remedied by using RAM that came with your machine, and see if that has an effect.

4. Logic board. This problem is usually linked to specific runs of machines, but heat seems to play a role. For example, Apple recently notified customers with an early 2011 MBP that they're at risk for this issue. The challenge here is that users may have disposed of the affected machines and moved onto something more reliable.

Nearly all the time, this issue will result from these four causes.

Every machine is reliable if it is built well and built properly.

do a fresh install with no Mavericks left overs on the machine, it appears to be running alot smoother… and more reliably…

Have you tried pram boots smc resets system diagnostics, with extensions off/safe mode etc?… 16gb is good… running only 8 I hear is fine as long as you are not running alot of software, TT Pro is great for problems above and beyond standard utilities.

Are you using Activity Monitor to see what is happening and checking crash logs to see if there is an app or process that is causing crashes?

New power points/vs old power points, machine is clean and free of dust build up, proper ventilation etc. all externals are running with proper cords, everything is plugged in properly… there are many things I could list here… externals are relatively new and in good working order or are maintained in good working order… Making sure you are shutting down on a regular basis and letting the machine cool/rest, dependant on what you are running, how much you are running and how you are running the machine; I talk to mine on a regular basis and give her rubs like a human, and it appears to work (know it sounds crazy but who cares; lol).

I've always found these guys handy in making decisions regarding machines, capabilities etc. http://mactracker.ca/

If you are running Yosemite try iStat Nano 2.2 Widget for checking temperatures pertaining to your machine,
it is the most reliable source at present from testing that have found… http://istat-nano.en.softonic.com/mac/download think this is it… 😉

Have tried most of those other fan controllers and they appear to make the machine run too hot with too many processes in the background
(or something to that effect/affect) with old installs of Yosemite over Mavericks and with fresh install of Yosemite.
Found one was running the internal fan really hard so it had to go…

If you are wanting to migrate upwards to Yosemite, do a fresh install and remove all remnants of Mavericks (make sure you have a cloned backup to refer to for system maintenance and in case anything goes pear shaped or south or wrong), there appears to be many issues with the past and the present colliding and driving temps up and processor to the max (as well as possible causing of mechanical failures).

If you are a Power user and using all associated (and purchased) utilities to maintain your system you shouldn't have too many problems, trouble-shooting app installation can be tricky, but if you install things sequentially and in proper running order everything should be fine as well as making sure all extensions and flash, java etc. are all the latest and greatest or waiting for the latest and greatest.

I hope this assists in moving forward, this is more of a general answer to several queries so I hope it makes sense to all and helps. Cheers

Concise and helpful information - thank you.

If only Apple inc. would acknowledge the problems and do something about it 😐

You're more than welcome Vanstar, in an Idealistic Apple World everything would be perfect, which would possibly remove any need for any infrastructure pertaining to Customer Service… (which is very individualistic based on actual use, Pro vs Consumer etc.)

Have since been using etre check to see what is happening and it's been helpful (after another sporadic unforeseen crash)… was concerned some Malware had slipped in somewhere somehow for which from appearance, appears to not have happened due to testing multiple apps that are not necessarily from the Apple Store.

In regards to my earlier assumptions that many of the fan controllers didn't work, so I removed them, is in fact incorrect, there appeared to be preferences left behind, after installs removed, so they were I imagine still running in the background and controlling fan temps and computer temps (which seems like an odd but reasonable assumption), I did some more testing and deleted the preferences, which was to my detriment as the machine was running extremely hot since waking this morning and the fans were going out of control… (Crazily so)

I have since tested further and found that http://www.crystalidea.com/macs-fan-control works with all settings (ODD, CPU & HDD) set to ambient control 21-31 degrees celsius (Correct at posting, possible change could occur, will see). And would imagine that this would vary dependant on environmental considerations. Will keep testing until all problems and bugs ironed out…

I find it odd that Apple has not taken this into consideration (I would imagine that Yosemite is a powerful operating system that with speediness of functionality needs a powerful machine), although I was concerned that EFI was no longer working with the upgrade as there was one quite some time back and was under the thought process that maybe it had changed upon upgrade.

Tried SMC Reset numerous times this morning with Fan Craziness (not much happened), & PRAM boots appear to be no longer working for which happen from a partition of Mavericks, that the system is still seeing and accessing before a full migration occurs. Stability is key. Once again this is another general if anyone needs the information answer, that may assist in their woes scenario.

Cheers

Off topic: Is anyone out there using Little Snitch, on their system and if you are, what are your thoughts on its functionality?

Is it a yes, no or maybe scenario?

Cheers

Off topic: Is anyone out there using Little Snitch, on their system and if you are, what are your thoughts on its functionality?

Is it a yes, no or maybe scenario?

Little Snitch is an excellent application that uses very little resources. Any time someone or something tries to contact you, typically software, you'll see a dialog box that gives you the choice to accept or reject the contact. Under normal conditions, you wouldn't even be aware of the intrusion.

In any case, it seems that you understand fully the importance of keeping your system temperature as low as possible. I've been using HD Fan Control for over a year, but the free software from http://www.crystalidea.com/macs-fan-control is extremely promising. It's really hard for a logic/graphics board to fry when your system has fan regulation.

We have created this petition for Apple. At least it might tell us how many people is affected by this:

https://www.change.org/p/apple-resolve-random-shutdowns-on-27-imacs

Oh~~~ Thanks for user maX2.lover to suggested using Macs Fan Control 1.3.0.

I had same problem of shutting down itself by iMac, just same as yours, Macs Fan Control was useful for controlling the fan and temperature of it, and I've tried using SMC fan control, but it seems didn't work, same issue happened again.

Since I've tried using Macs Fan Control 1.3.0 for few days, my iMac was haven't happen of shutting down by itself again. Perhaps it maybe too early to say, but I really think it works, because my iMac was shutting down by itself 4-5 times a day before using this app, then it haven't happen now.

Really thanks for introducing this app.