iMac powering off AND on randomly
40 days ago my 2017 27” iMac started powering off and on randomly. It would stay on for anywhere from 10 seconds to a few minutes, shut down again, and also randomly power up again. As on old ACSP, I did all the tricks I can think of and then brought it to Apple, who couldn’t replicate the issue of course. So I brought it home again and it worked fine for 40 days, but now it’s doing it again.
What I find interestIng is that often right before it shuts down, I see the shut down dialog (are you sure you want to shut down…) appear. It’s also interesting that it powers on again after a few seconds or minutes. Haven’t yet found another case that mentions these things. Anyone have reason to believe it’s anything other than a bad power supply? BTW also keep this iMac on a UPS with AVR. Any advice is appreciated.