Finding my iMac powered off in the morning

[SDColorado]

My late 2015 iMac has suddenly been powering off at random times. I mostly find out its off in the mornings. I am unable to power it back on by pushing the button and the only thing that allows me to power it back on is if I remove the plug from the back of my iMac, wait for about 30 seconds, then plug it back in. My iMac will then boot up. I tried resetting SMC and PRAM.

Question is, is their any logs that could help me determine what is happening? Maybe I have a bad power supply?

I have had this same issue occasionally. I also have a 2015 5K iMac . Like your follow up post to this, also no error messages. I think I am going to book it in to the Genius Bar and have them run a diagnostic, because I can't figure out why it does it and why it does it infrequently and randomly

 

[Raist3001]

I have had this same issue occasionally. I also have a 2015 5K iMac . Like your follow up post to this, also no error messages. I think I am going to book it in to the Genius Bar and have them run a diagnostic, because I can't figure out why it does it and why it does it infrequently and randomly

When the Apple store had my iMac, none of their diagnostic tests could shed light on the issue. Luckily, they were able to reproduce the issue in their testing room. That and I had many videos showing the issue. In my case thankfully, apple is giving me a brand new iMac. And best part is, I get to purchase apple care again. I will be covered for another 3 years.

 

[SDColorado]

When the Apple store had my iMac, none of their diagnostic tests could shed light on the issue. Luckily, they were able to reproduce the issue in their testing room. That and I had many videos showing the issue. In my case thankfully, apple is giving me a brand new iMac. And best part is, I get to purchase apple care again. I will be covered for another 3 years.

That is definitely good news. My worry is that they will not be able to reproduce the error, since it is infrequent and may require many fruitless trips. But maybe they know what the issue is and how to possibly trigger it?

 

[Raist3001]

That is definitely good news. My worry is that they will not be able to reproduce the error, since it is infrequent and may require many fruitless trips. But maybe they know what the issue is and how to possibly trigger it?

I was experiencing shutdowns daily which allowed me to capture the issue on video later on. On my first visit though, I had nothing but my word, and the genius was unable to reproduce the issue at the genius bar. At first, the store was not going to take in my Mac. They claimed it was a software issue, and that I needed to re-install the OS. This did not make sense since I was unable to power the Mac back on with the power button. I needed to ask for a manager who agreed and then they took my Mac in and replaced my power supply. You may have to be a bit stern, but I believe apple knows of the issue. Too many people on the internet have this problem. Its a hardware issue and not software.

 

[SDColorado]

I was experiencing shutdowns daily which allowed me to capture the issue on video later on. On my first visit though, I had nothing but my word, and the genius was unable to reproduce the issue at the genius bar. At first, the store was not going to take in my Mac. They claimed it was a software issue, and that I needed to re-install the OS. This did not make sense since I was unable to power the Mac back on with the power button. I needed to ask for a manager who agreed and then they took my Mac in and replaced my power supply. You may have to be a bit stern, but I believe apple knows of the issue. Too many people on the internet have this problem. Its a hardware issue and not software.

Mine has been infrequent. Only a couple of times a month maybe. It will be hard to show much evidence. For now it is nly an annoyance, but I do worry that it will continue to get worse and when it does, it will be out of warranty.

 

[Fishrrman]

OP:

A question.
Do you have your Mac's software update preferences set to automatically download and install updates?

 

[SDColorado]

OP:

A question.
Do you have your Mac's software update preferences set to automatically download and install updates?

I know I am not the OP, but since I am having a similar issue, hopefully I can chip in an answer. I do not have preferences set to automatically download and install updates. I don’t like updates being installed without having the chance to review them.

 

[Raist3001]

OP:

A question.
Do you have your Mac's software update preferences set to automatically download and install updates?

No I do not.