Recurring iMac problem during OS updates: any ideas?

[michaelsaxon]

Hello, I have a loaded up 27" iMac that is the last one from the Intel era. When I do an OS update, it inevitably gets somewhat through the process, turns itself off as to be expected, then the Apple symbol never appears and the power button becomes useless to get it on. I've tried all combinations of resets, power cord removals, etc., to no avail. Last time this happened the Apple Store fixed it in a few days, something to do with reinstalling the bios I think they said. Sadly, it just did it again during another step update. Any ideas or am I stuck bringing it back to them and then not updating from this point forward? Thanks.

 

[Bigwaff]

I have a loaded up 27" iMac that is the last one from the Intel era

So it is 2020 Intel iMac? Model number and more would be helpful here.

Try running Apple Diagnostics. Maybe hardware issue?

Use Apple Diagnostics to test your Mac - Apple Support

Apple Diagnostics, formerly known as Apple Hardware Test, can check your Mac for hardware issues.

support.apple.com

 

[zarmanto]

So wait... you're saying that you've unplugged the power cord and plugged it back in, and the power button still does absolutely nothing?

That, my friend, should never happen.

And you say this isn't the first time, and that the Apple Store repaired it last time... how long ago was that?

 

[michaelsaxon]

Inexplicably, some combination of removing the power card, plugging it back in, holding the button at length, etc., finally yielded an Apple and a completed OS update. I'm back in business. Honestly, it does this craziness each time I do an OS update. It will just shut itself off and never come back on without some combination of some actions that never seem to be the same.

 

[Terraaustralis]

As Bigwaff states, it would be helpful if you gave us the year and model number so we can respond more helpfully.

 

[michaelsaxon]

It is fixed now.