27" iMac shuts self down and will not turn on unless unplugged first

[JordanKyle94]

My iMac is around 14 months old and is used for around 3-4 hours a day 5-6 days a week, for the last couple of weeks it keeps shutting itself down and won't turn back on unless the plug is removed from the back of the monitor first and replaced, happens at least once a day, sometimes more.

All it's software is up to date and there have been no issues in the past, can anybody help?

 

[keysofanxiety]

My iMac is around 14 months old and is used for around 3-4 hours a day 5-6 days a week, for the last couple of weeks it keeps shutting itself down and won't turn back on unless the plug is removed from the back of the monitor first and replaced, happens at least once a day, sometimes more.

All it's software is up to date and there have been no issues in the past, can anybody help?

What peripherals do you have plugged in? Any USB hubs or similar?

Are you running El Capitan (10.11.6)? Could you advise the full model/year/specification of your iMac?

 

[JordanKyle94]

The only USB plugged in is the one connected to the external disk drive, Everything else is wireless.. (Headphones, scanner, printer)

I'm currently running version 10.10.5 but to be honest I have no idea what that means.

I'm not sure to get any other information for you without instructions sorry

 

[keysofanxiety]

The only USB plugged in is the one connected to the external disk drive, Everything else is wireless.. (Headphones, scanner, printer)

I'm currently running version 10.10.5 but to be honest I have no idea what that means.

I'm not sure to get any other information for you without instructions sorry

Not to worry at all. The details you have provided are very useful!

It may be worth to start by updating to El Capitan (10.11.6). You can do this by opening the App Store and clicking the 'Updates' tab. This may show El Cap along the top of that window. Otherwise, you can just search for El Capitan within the App Store.

Does the machine randomly shut off when you're using it? Completely turn off with a black screen? Is it when you're doing anything in particular?

 

[JordanKyle94]

I shall update it after posting this and keep you notified!

It currently has no sort of pattern it fits into, it just happens randomly and different times. The entire screen goes black, music shuts down and it wont turn back on no matter how long it is left unless it has been unplugged at the monitor first.

It takes double the time it usually does when powering back up and when I open Chrome again my pages are still there and reset themselves.

 

[merkinmuffley]

Interesting, I'm seeing something similar in my IMac. Won't wake up from sleep unless power cord is pulled for about 15 seconds and plugged back in. I've reset SMC and NVRAM, neither fixed it. I've got an appointment tomorrow with the genius bar, maybe they can find something wrong. I'm running 10.11.5, I7, purchased it new in May 2016.

 

[keysofanxiety]

I shall update it after posting this and keep you notified!

It currently has no sort of pattern it fits into, it just happens randomly and different times. The entire screen goes black, music shuts down and it wont turn back on no matter how long it is left unless it has been unplugged at the monitor first.

It takes double the time it usually does when powering back up and when I open Chrome again my pages are still there and reset themselves.

Okey dokey, may also be worth quickly checking the HDD SMART data through SMART Utility, just to ensure the drive is fine. You can download that application by following this link: For 10.9 to 10.11

When you shut down normally (recommended every few days), also ensure that reopen windows when logging back in is disabled/unticked.

If it's hardware, it could potentially be graphics/mainboard from what you've described, though we'll obviously see what the news is once you're on the latest OS.

Best wishes & speak with you soon.

 

[JordanKyle94]

Good morning! After downloading and installing El Capitan within 30 minutes of using the Mac it shut itself down again in the usual fashion.

Maybe it's a different issue?

 

[In Utopia]

Good morning! After downloading and installing El Capitan within 30 minutes of using the Mac it shut itself down again in the usual fashion.

Maybe it's a different issue?

My iMac is doing something similar.
Today I went to print and it shut down.
Opened a new tab tried to load it, shut down.
Big difference is I have to hold the power button while pressing the control and command keys until it starts booting.

 

[JordanKyle94]

Since updating to El Capitan I cannot play Sims 4 for longer than 20 minutes without it shutting down.. I haven't tested general use yet but I'll update you as soon as I know anything

 

[JordanKyle94]

I spent 5 hours online last night streaming, social media & netflix without a single shut down
[doublepost=1472733564][/doublepost]

 

[Fishrrman]

Could be a heat or GPU issue…?

 

[todds89]

So, just last week, my 13 month old mid 2015 27" iMac Retina is doing the same thing.... my wife uses it for photo / video editing...

 

[Matejh]

Same issue with iMac 27 Late 2012. Interesting is that it was switching off with original HDD, than with SSD same thing. After that logic board was replaced and now same thing. It switches off after few minutes and then has to be disconected from power for few seconds before it turns on again.
Is it possible that power supply is faulty? What do you think?

 

[drambuie]

It could be that the power supply is sensing an overvoltage or overcurrent condition. In either situation the sensing circuit will shut down the power supply and latch, maintaining the shutdown until input power is removed. Even a very momentary short will trigger the latch.

The overvoltage sensing circuit is commonly referred to as a crowbar, because if an output overvoltage is sensed, it will cause an instantaneous dead short that will trigger an overcurrent shutdown. This protects the load.

An overcurrent situation is usually caused by a defect in the load, whereas an overvoltage shutdown is most likely due to an internal power supply fault, but this is more likely in series regulated supplies rather than the switching regulated supplies used in computers. Faulty sensing circuit defects could also trigger shutdowns.

Unfortunately, intermittent faults like these, with multiple potential causes, are very difficult to diagnose.

 

[todds89]

Ok, so just a few things that I've tried today, to no avail.

1. Removed the 16gb of Crucial Ram that's been in there for almost a year
2. Updated with latest OS X El Capitan version

Seems like it dies after a couple hours, last 2 times when I selected a new tab in Safari

 

[merkinmuffley]

Just picked mine up from the local store after a repair. They replaced the logic board and power supply. So far it looks good, need to let it sleep over night and see what happens. $730 repair, glad it was under warranty.

 

[todds89]

Another short update - just ran Apple Diagnostics and no problems were found...

 

[pbarra1]

My iMac is around 14 months old and is used for around 3-4 hours a day 5-6 days a week, for the last couple of weeks it keeps shutting itself down and won't turn back on unless the plug is removed from the back of the monitor first and replaced, happens at least once a day, sometimes more.

All it's software is up to date and there have been no issues in the past, can anybody help?

SMC reset?

 

[Dekkarino]

Hello, the imac 5k retina of my sister has the same problem after patching up to 10.10.4

It's a common problem neither apple can resolve as i can see.

Only think they do is changing logic board and switching


The things that i did: stop using safari, reset smc and pram, using wifi instead of wired, disconnect all usb port.

Now i will try to disable icloud (seems a possibile problem)

The last try is to install macosx sierra and have fingers crossed

 

[todds89]

Ok, so still having the issue...

Called Apple support last night - they had me reinstall OSX... of course, that didn't help.

Any more ideas?

 

[merkinmuffley]

Set up and appointment with the genius bar and let them take a look at it.

 

[binurajk]

Interesting, I'm seeing something similar in my IMac. Won't wake up from sleep unless power cord is pulled for about 15 seconds and plugged back in. I've reset SMC and NVRAM, neither fixed it. I've got an appointment tomorrow with the genius bar, maybe they can find something wrong. I'm running 10.11.5, I7, purchased it new in May 2016.

Hey, did you get your iMac fixed? Mine is showing similar issues and I'm wondering what should I do next. Please let me know.

Thanks!

 

[kerrikins]

Hey, did you get your iMac fixed? Mine is showing similar issues and I'm wondering what should I do next. Please let me know.

Thanks!

Think you missed this post of theirs:

Just picked mine up from the local store after a repair. They replaced the logic board and power supply. So far it looks good, need to let it sleep over night and see what happens. $730 repair, glad it was under warranty.

 

[Trebuin]

I've had that before...power board inside failed. Contact apple & they will replace it. Exact same symptoms: randomly powers off, will not power on again until you unplug the cord.