My Mac Restarts After Being Idle for a long time

I reactivated my account on Apple Support Community just to reply to your solution.

I had been experiencing the same problem... since 2019. I was using a fully specced 2019 MacBook Pro 16-inch. I dropped it on the first week and the lower-right corner of the screen had a tiny glow. It didn't affect graphics at all and I was relieved that there was no other damage aside from a dent. Except that my MacBook would now restart when left idle.

All that time, I attributed that daily scenario to the drop. Maybe a wire got loose or a chip cracked somehow? All my searches online were what people called a kernel panic. And for years, I would go check forums and support communities and Reddit about how people solved — or, at this point, lived with — this issue. From 2019 to 2024. Five years. Just searches on kernel panic. And it baffled me how I don't get prompts upon restart and nothing shows up in the crash reports in Console.

I finally got an M3 Pro MacBook this month. I upgraded because the 2019 one already slowed down that it's unbearably useless and the keyboard is absolute whack, but also in the hopes that these daily restarts would go away. Surely, I couldn't be so unlucky that two really expensive Macs would act up?

I used Migration Assistant (which copied everything including system settings) because I had too many files and too many settings I did not bother to download from scratch. When that finished and I had everything I needed, I left it for a while and, you guessed it, it restarted.

I decided, heck, let's just start from scratch. Migration Assistant said it transferred 1.1 million files, can't be too bad. I did just that, started fresh and installed Dropbox to start downloading all my files. While it was doing that, I left the house to let it do its thing and, as I have been doing for five years, I checked online to see if someone finally found a solution to this problem. And that's why I'm here writing this whole essay, just to say that the past five years just flashed before my eyes. All my disappointments with the Mac, all my frustrations when I'm doing work and I come back with a restarted laptop and needing to reopen everything, all those times when I thought the only solution was to open a blank Pages document, type the letter A and leave it without saving just to stop the Mac from restarting — all gone with a single toggle.

Not to say that I have saintly patience, but if saints were to go through what I went through, I doubt they'd make it this far without losing their sainthood.

Oh, and, thank you.

dennisat wrote:

Whenever I leave my Mac inactive for around 2 hours, it restarts by itself without showing any errors. After the restart, it goes to the login screen, and after login all my apps seem fine without any sudden shutdown issues. Even the Console app doesn't report any problems or crashes!

Although there's no technical problem per se, reopening all my apps is annoying.

I've tried changing settings related to Battery, Energy, and Screen Saver, in various combinations, but I couldn't find a consistent pattern.

Then I discovered something interesting: it restarts when I leave my Mac idle for about two hours with the power cord connected. But if I leave it idle without the power cord, it doesn't restart.

I've checked the setting "Turn display off on power adapter when inactive," but it's turned off.

This problematic behavior has been occurring since I purchased this Mac, which was approximately a year ago.

you must have the patience of a saint 🤣

Verify your settings....make changes to suit your needs

ref: Set your Mac to log out when not in use - Apple Support

@francisborja

Thank you for the essay, as you say, above. With the exception of a Word document instead of Notepad, you've described the last four years of my life. Except this hidden setting was set at 20 minutes for me. Every so often, when I got fed up coming back to another restart, I'd do research and see the same advice about kernel panic, and never a solution. Bought a new mac, used Migration Assisstent, had the same issue. I'd resigned to the fact I might have to just take it in and beg for help.

As they say, misery loves company, and while reading your post I couldn't believe how similar are issues and "solutions". All this to say, thanks for posting and I too and so relieved to at last, have an answer.

ah thank you! I completely forgot about that hidden setting lol