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iMas70

macrumors 65816
Original poster
Sep 4, 2012
1,440
207
MA
My 27" iMac has been restarting every night. I didn't think much of it when it first happened a week or two ago. I figured maybe the power went out or there was an update. But it keeps doing it. And sometimes, it won't wake up when I move the mouse or press a key so I have to hold the power button down to restart. I get the ‘your computer restarted because of a problem’ message. I did a search and found someone experienced some of this. It ended up being a RAM issue. Could it be that or something else? I just checked my Applecare coverage. I have that for another year so I'll contact Apple if it keeps happening. The configuration is -

iMac (Retina 5K, 27-inch, 2017)
4.2 GHz Quad-Core Intel Core i7
40 GB 2400 MHz DDR4
Radeon Pro 580 8 GB

Thanks!
 

iMas70

macrumors 65816
Original poster
Sep 4, 2012
1,440
207
MA
To me this does sound most likely to be a ram issue

I'm thinking I should take out the aftermarket RAM to see if that fixes the problem. It's been in there since I bought the computer.
 

Fishrrman

macrumors Penryn
Feb 20, 2009
28,729
12,843
How much RAM is installed NOW?

You could:
- Take out the 3rd party RAM and leave the factory RAM in.
or
- Take out the factory RAM and leave the 3rd party RAM in.
or
- Try both approaches and see what works best.
 
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iMas70

macrumors 65816
Original poster
Sep 4, 2012
1,440
207
MA
How much RAM is installed NOW?

You could:
- Take out the 3rd party RAM and leave the factory RAM in.
or
- Take out the factory RAM and leave the 3rd party RAM in.
or
- Try both approaches and see what works best.

I currently have 40GB installed. The computer wouldn't wake up this morning. I tried tapping keys on the keyboard, moving the mouse and the trackpad. So I had to push the power button to restart. So now I'm paying attention to what happens and when. I'll keep notes on that until the end of the week. I could be wrong but it seems that this only happens in the morning. If that is the case, I'm wondering why.

Something else that I've noticed is when I'm in Safari on my phone/iPad, I can't see the tabs that are open on my iMac. I used to be able to. I've checked the settings to make sure the box is checked off. I can see what is open on my iPhone and iPad while on the iMac. It's probably not related but I figured I'd mention it just incase.
 

iMas70

macrumors 65816
Original poster
Sep 4, 2012
1,440
207
MA
I've been keeping notes this week. I've had to manually restart the computer each morning. It wouldn't wake up when I move the mouse or press a key. I took the OWC RAM last night. Same problem this morning. Last thing left before I call Apple is to replace the factory RAM with that. I'll do that today.
 

Albert2011

macrumors newbie
Dec 18, 2020
9
1
I had a similar issue with a 2 year old 27" iMac when I added 16 GB OWC RAM to the existing 8 GB Apple installed RAM. Removal of the original Apple installed RAM resolved it.
 

rpmurray

macrumors 68020
Feb 21, 2017
2,148
4,321
Back End of Beyond
I remember reading reports from some people reporting that their iMacs would wake in the middle of the night to check for updates even though they'd been put to sleep. It could be that it is doing that but that an update is either doing a restart that fails or it's failing in such a way that a restart occurs. You may want to open the Console application and check if there are any reports of a problem overnight. You could also try checking if there are any updates available for the iMac and manually install them. I'm more inclined to believe that it's a software problem rather than hardware since it seems to happen on a schedule. Another thing you could do to test would be to restart the iMac in Safe mode then put it to sleep and see if the same problem occurs overnight. If it doesn't then you may have some software installed that is triggering this. Google is especially notorious for including in their software automatic background updaters that can cause problems.
 

iMas70

macrumors 65816
Original poster
Sep 4, 2012
1,440
207
MA
I installed Big Sur update 11.2.2 this morning so it's up to date. I'm home today so I've been on and off the computer. I find that it has a hard time coming out of sleep mode. I've had to power it off and on a few times. So besides the late night restarts, I'm also dealing with this. I'll try your suggestions and will be adding calling Apple to the top of my "to do" list.
 

rpmurray

macrumors 68020
Feb 21, 2017
2,148
4,321
Back End of Beyond
Is the drive in the iMac a Fusion drive? Fusion drives have hard drives that take a while to spin up so may be slowing down the wake process. Similarly do you have any external hard drives attached?
 

iMas70

macrumors 65816
Original poster
Sep 4, 2012
1,440
207
MA
It's a 1TB SSD. I had a couple of external SSDs attached. I unplugged them when I took out the aftermarket RAM.
 

dimme

macrumors 68040
Feb 14, 2007
3,125
29,447
SF, CA
I am having an similar issue on a 2019 iMac. I had the machine almost 2 years. The last 2 months I have been having the machine turn off when sleeping or restart with a message that I have had a sleep wake efi failure. I did a fresh install of Big Sur and disconnect half Of my usb devices
 

rpmurray

macrumors 68020
Feb 21, 2017
2,148
4,321
Back End of Beyond
I'm wondering if this might be because the BR2032 battery on the logic board has died. They should last longer than this but if it is indeed the problem then it might be a little tricky getting into the iMac to replace it.
 

iMas70

macrumors 65816
Original poster
Sep 4, 2012
1,440
207
MA
I wasn't around on the weekend so I didn't get a chance to call Apple. I anticipate it being a long call so I have to block off a couple of hours. I no longer know if the computer is restarting at night. I haven't been able to wake it up when I start my day so I have to manually power it off.

A couple things that might or might not matter with this -

I just checked the Energy Saver to see when the hard driver is scheduled to sleep. The box that says "Prevent the computer from sleeping automatically when the display is off" box was checked. I just selected "restore defaults" to see if that changes anything.

When looking at my iPhone/iPad then Safari then open tabs on all devices, I don't see the Safari tabs that are open on this computer. I recently added two other Macs to my iCloud and can see what is open on them.
 

iMas70

macrumors 65816
Original poster
Sep 4, 2012
1,440
207
MA
Above I noted - I just checked the Energy Saver to see when the hard driver is scheduled to sleep. The box that says "Prevent the computer from sleeping automatically when the display is off" box was checked. I just selected "restore defaults" to see if that changes anything.

The computer woke up after I tapped my mouse this morning. I don't know if/how this ties in. Seeing that I didn't have to manually start the computer, I could see that it didn't restart overnight and no problem message.
 

Ledgem

macrumors 68020
Jan 18, 2008
2,038
931
Hawaii, USA
These days, it could be practically anything:
1) Software;
2) the RAM;
3) external devices.

In my case, I have had a surprising amount of system instability due to what I've narrowed down as USB hubs. It's usually not a matter of kernel panics, but comes in the form of external drives spontaneously ejecting; I have two hubs and removing one initially fixed all issues... although after upgrading to Big Sur I had lots of drive ejections and kernel panics, that resolved after unplugging the remaining hub (which had previously been working fine for years). Now slowly adding back the USB-connected devices to determine if it was just one port on the hub, the entire hub itself, or if one of the devices that was connected was causing problems. And even then, I've read that sometimes it's not the device, itself, but the cable... plenty of trial and error ahead.
 

iMas70

macrumors 65816
Original poster
Sep 4, 2012
1,440
207
MA
Day 2 after changing the Energy Saving setting. I think it's fixed.
 
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