Mac Mini mid 2011 restarts when idle, but works fine on heavy load

Question

Mac Mini mid 2011 restarts when idle, but works fine on heavy load

Hello. Please help me if you can. Any advice is highly appreciated.

My Mac Mini mid 2011 with dedicated GPU AMD HD 6630 worked great for years. High Sierra with all latest updates. It is my work machine, so I use it for many hours every day. But a couple of months ago it started to reboot when it is in sleep mode. I thought it is a software issue, so I turned sleep mode off and forgot the problem. For some time. Then it started to reboot every time immediately after it is put to sleep (I did it occasionally, as I used active corner for sleep mode). Ok, I turned off the active corner and forgot about it for some more time. But few weeks later it started to reboot even when it is not in sleep mode. But it happened only when it was idle for more than 2 minutes. When I used keyboard or trackpad, Mac mini worked fine, but when I left it for few minutes, it rebooted. And then again, and again. But when I started to use it, it worked fine again. At this time it booted with some problems, every third or fourth time, but when it booted correctly then it worked normally. I had adopted for this new regime and worked with this a couple of weeks more. And finally yesterday it started to reboot even when I work with it. And I found a workaround again. It does not reboot when it runs any task that consumes resources. For instance, I opened YouTube stream 1080p in a little window, and now it does not restart. For all night long. If I close window, Mac mini restarts in a couple of minutes.

What I have tried already:

- SMC, NVRAM reset.

- AHT — no errors.

- Memory modules (used every one as single one in every slot). Swapped, shuffled, cleaned etc.

- Clean install of High Sierra from App Store.

- Apple SSD, Samsung HDD, different SATA cables, different SATA ports at the logic board (lower and upper).

- Boot from USB with SATA-USB adaptor.

- Disassembling, dust cleaning. I even replaced thermal grease between CPU, GPU and cooler.

- Disconnected bluetooth/wi-fi module.

Safe boot. It works great in the safe mode. It does not reboot itself, even the sleep mode works fine. I can't figure out what to do with this knowledge.

I can't figure out if it is a software or hardware problem. It is weird, when the computer works great under a heavy load, but fails when idle. Please help me if you can.

Mac mini, 10.13

Posted on Apr 22, 2020 4:50 AM

Reply

Answer 1

Best reply

den.thed

Level 9

77,074 points

Apr 22, 2020 8:18 AM in response to Andrii Zaiats

That is a strange problem.

I've upgrading a dozen or more 2010-2012 Mac Mini's and never experienced that kind of problem. I did have to redo the paste on a 2011 because the heat sink lost contact with the CPU and wasn't cooling properly.

At this point, I suspect that you could have at least two of the following problems.

The power supply is failing.
The power supply is not properly grounded to the case.
The logic board has a bad or weak ground connection to the case.
There is a weak solder joint or connection somewhere on the logic board.
The GPU/CPU or some other component is over heating and causing a thermal shutdown.

I use MacFanControl on all of my Mac's to help look for any thermal overheating problems,

https://crystalidea.com/macs-fan-control

Right now my 2012 Mac Mini is running fairly cool with just Safari and iTunes running.

Reply

Answer 2

Apr 22, 2020 8:47 AM in response to den.thed

Thank you for your reply. I do not believe it is a heat-related problem, as it repeats every time I follow certain steps. If I put it to sleep, it restarts immediately. If I disconnect HDMI cable, it restarts immediately. Every time. If I run Geekbench Compute benchmark (very heavy load, a lot of heat, full-speed fans) it works fine for hours.

Follow your suspicions about weak contacts, I tried to shake the Mac a little. Nothing happens. Then I disconnected HDMI, and it restarted instantly.

I found another person, who has very similar problem with Mac mini mid 2011. And he posted his question here just 5 days ago. So now I think it is a software related problem, even though I have made a clean install of High Sierra from App Store. Maybe this problem is caused by some software update, and I think App Store's High Sierra installation package has all updates included.

I'm going to install an older macOS version.

Reply

Answer 3

den.thed

Level 9

77,074 points

Apr 22, 2020 10:19 AM in response to Andrii Zaiats

OK then next, I would try downloading and installing the 10.13.6 Combo Update over the top of the current Mac App Store 10.13 macOS version. > https://support.apple.com/kb/DL1970?viewlocale=en_US&locale=en_US <

Reply

Answer 4

Apr 23, 2020 12:44 AM in response to den.thed

As for now I have tried 4 different sources:

current 10.13.6 with all updates applied from my SSD
clean install of 10.13.6 from App Store
downloaded 10.13.6 from 2018
and even El Capitan from old HDD from a shelf.

No success.

Reply

Answer 5

HWTech

Level 9

55,604 points

Apr 22, 2020 7:45 PM in response to Andrii Zaiats

Since you have a third party SSD installed try disabling "Put hard drive to sleep when possible" located in the Energy Saver System Preferences. Some SSDs don't wake from sleep very well. Plus some third party SSDs are not always compatible with older Macs with SATA II controllers.

Reply

Answer 6

Apr 23, 2020 1:15 AM in response to HWTech

My SSD is not a third party one. It is APPLE SSD TS256C installed by Apple. And I turned off all check boxes in the Energy Saver pane. Mac mini restarts immediately after go to sleep, not on wake.

Also I tried different HDMI cables. It restarts every time I disconnect HDMI cable even if it is not connected to the monitor on other end. It is not a bad contact. It happens every time with different cables. And it never happens while in safe mode.

Now I think it is a video related issue. What I have as for now:

1) it restarts on sleep or on HDMI cable disconnect;

2) it restarts when idle (not in sleep), but works for hours when playing HD video in background.

2) it works with no problems when in safe mode. Sleep, HDMI disconnecting, idle, heavy load, shaking — nothing can make it restart when it is in safe mode.

3) the problem persists even if I try El Capitan from old HDD.

I found that Apple updated video related kexts on March, 20. I suppose they could install some new firmware to my Mac mini. GPU firmware or something.

It can not be a software problem, as I tried different installs and different OSes. And it can not be a pure hardware problem, because it works differently in safe mode and normal mode (HDMI disconnecting).

Reply

Answer 7

Apr 30, 2020 12:09 PM in response to Andrii Zaiats

So I found it works fine with Bluetooth off. I replaced Magic Keyboard and Magic Trackpad with generic USB keyboard and Microsoft mouse. No crashes on startup, no crashes while working.

All I have to do now is waiting for next Security Update 2020-003. I hope Apple will ship new Boot ROM and fix it. 🤞

Reply

Answer 8

May 13, 2020 8:02 PM in response to Andrii Zaiats

Sorry to say, Bluetooth 'workaround' was not real solution. It made restarts more rare but did not solve the issue completely.

I tried to figure out what device is the cause of restarts. I tried different kexts comparing Safe Boot and normal mode. And finally I found that without AMDRadeonX3000.kext, system starts every time, it does not restarts randomly, it does not restart on sleep and on HDMI cable disconnect. Now there is no 3D acceleration, but at least it is working stable now and much faster than it does in Safe mode. Now I can use my Mac mini again.

Reply