Mac keeps restarting for no clear reason.

I have a Mac Pro tower mid 2011, Xeon two quad cores. After installing Mac Mojave my computer kept restarting then not starting. I tried everything from replacing CR 2032 battery, to changing my graphics card, to pushing all sorts of button combinations, testing my Power supply - it was working fine, to taking out the CR2032 and letting the computer sit without power for 48 hours( which has worked for me before on earlier towers and MacBookPro, lately.

As a last resort I put in a Windows 10 hard drive( having seen a couple of Mac Book Pros using Windows 10) and I am happy to report my Mac is working perfectly.

I had some problems after installing High Sierra a few months ago and I believe that Apple is inadvertently damaging computers which it says are compatible to it’s new systems but is not. I doubt very much that Apple is going through the process of dragging out older Macs and testing their newer systems on them one at a time. I suspect that that they merely applying a formula with regard to basic common elements( like does the computer use DDR3, is it an Intel chip based machine, can it support adequate graphics and so on.) I also think that they have upgraded my firmware incorrectly.

I dislike Windows generally but I spent 800$ for this machine - Windows isn’t that hard to use!

Unfortunately, replacing power supply did not help. The shutdowns kept getting more and more frequent. Since there is no new Mac Mini's from apple, I am experimenting with a hackintosh, based on an Intel NUC.

Did anyone ever come up with a solution for this? My 2012 Mini has the same problem. It was my media server, so now I've replaced it with a Windows 10 PC. The mini is now in my workshop. A faulty power supply does seem like a plausible culprit for the random rebooting. I am toying with the idea of removing the existing power supply and powering it with an external 12 VDC power supply. Any thoughts? Am I wasting my time?

Mine does this too. Just shuts down likes it a scheduled power saving thing or something. If I’m using the computer it’s fine. If it’s left alone, it tries to shut down after 20 minutes. Was hoping to use this as a media server but it’s useless. Very frustrating as I’ve adjusted every setting I know to address.

i have the same problem with my mac mini 2011 and i don’t understand how apple can make this upgrates wich many computers it’s getting broke. until el os x capitan was fine but after it was just for distroy the computers,. i look on the youtube and some people have been fix this problem by change an a capacitor. Can be true? any solution?

I think the motherboard is broken. Like MacBook Pro 2010 it had the same problem and I had to replace one capacitor, after works fine.

I am having the same problem guys, and it started … I don’t know why. I installed still the High Sierra, but noticed that was too slow and did not bring any new features. I went back to El Captain, which runs “perfectly”. but since about 2 months, the macmin keeps ramdonly restarting. In hardware did not touch since abot 3-4 years is running with the same one and as no changes, I can not believe something is wrong with it! Hardware is simple, works or not working.

I did a 2nd partition on the SSD and re-install new El Captain, without any external software, and it keeps doing it …

now my next step is erase completely the SSD, as hard as possible, and try to install the original Lion … and go from there, that I will do it this week, meanwhile I am assuring no loss of data before the erase operation

I disagree with the power supply diagnosis. Unless you have set your power save options to restart after power fail, the machine will stay off. Mine does not stay off. None of the others reporting this issue claim it stays off.

I was having the random restart problem several times per day after updating to High Sierra. The suggestions above caused me to start thinking about what functionality might change across releases. I decided to look at Power Save options.

I disabled power save for both system and display (set it to Never). The problem has disappeared. I have been running for a week now without recurrence.

It appears that Apple has introduced misadventure into the Power Save behaviour of (at least) High Sierra on Mid-2011 Mac Minis.

Having same issue, high Sierra 10.13.6 on a mid 2011 Mac mini.

So far, I’ve backed up all files to an external hard drive using time machine. Also wiped the OS drive for a fresh install. I’m currently migrating all old files all back to the fresh OS drive.

During this process, the Mac mini has restarted, so I’m guessing a fresh install isn’t the fix for me.

Im also seeing High Sierra is a common factor with the boot issue. I’m going to try and update to a newer os if it’s even possible. If not I’m guessing a hardware issue?

Same problem here. The most strange part is, Windows 10 via Bootcamp works fine. As soon back on OSX, it start to crash again (sometimes when booting). That why I don’t think its a hardware problem.

I was that stupid to try to fix it by wiping the harddisk, now I don’t have windows anymore :(

Thanks to droolinggeezer. Yes for the older mac mini, it need to disable all option to the power saver. It worked for me on the latest 2014 mac mini. Solved my rebooting issue after the fresh new hard drive (hd) installed. I thought the hd had issue but it’s not. It had the same issue with the new replaced hd. I am not sure why Apple does not know about this issue and do something to fix this issue? I will raise this issue the Apple tech support. They were on the phone with me for 1.5 hour trying to install and reinstall the macos operating system.

I see that this thread isn't completely dead yet. What I was experiencing was a snow/static screen and a restart, and this would happen whenever I would edit a video. After trying everything I knew of, a reflow of the cpu/gpu is what solved the issue for me. No not in an oven, but using a bottom heater and a hot air station and flux. I previously tried/ruled out

• using a Thunderbolt Display instead of HDMI
• hard drive, including getting the same result with a clean installation of Mojave on external ssd
• memory
• heat/fan
• virus/malware
• power save settings
• pram reset
• diagnostic startup

I'm having this issue with my Mac mini (late 2012) Quad-Core Intel Core i7 2,3 GHz running MacOS Catalina v10.15.7.

I have an Apple Thunderbolt display and HDMI monitor attached to it.

Changing the power saving option solves the issue but I don't want to continue using this "workaround" for my Mac mini.

Power save settings when issues occured:

Computer sleep: after 30 mins

Display sleep: 15 mins

Crash/reboot issue occurs after waking up the computer from sleep mode.

Updated Power save settings - no more issues:

Computer sleep: never

Display sleep: 15 mins

Crash/reboot issue no longer occurs after waking up the display.

Conclusion: the issue is clearly coming from the Mac mini resuming from sleep mode since it no longer happens with the updated settings that doesn't put the Mac mini to sleep mode. I don't think it has anything to do with the OS since some people are seeing this with High Sierra but I'm using Catalina.

Current workaround power save setting is not my preferred one since it keeps the mac awake and is consuming power all the time.

I will probably be doing some more tests in the coming days/weeks.