I updated my MBP (14-inch M1, 2021) to MacOS 13.3.1 yesterday. There were no problems but, as usual, during the process the Mac went completely silent (what I call the dark side of the moon) for about 10 minutes while updating.
It’s starts with the progress bar, and an estimated time left. Then just goes dark for a time. I’m tempted sometimes to force a restart, but I don’t want to mess anything up. So I sit there and stare at it and try not to be nervous.
Eventually the Apple mark returns and the process continues, and there is one or two more apparent restarts and it’s done.
During the dark time is there any way at all of detecting that the Mac is still, in fact, on and doing something?
The caps lock light is of course still there and in principle cold be used (like alerting users that it will be blinking to indicate the Mac is still updating despite otherwise looking as if it crashed), but that would require Apple be convinced users need feedback during the process and then going out of their way to program that (at the low level required). I don’t see any indication they believe that type of feedback is really necessary or would justify the effort. Personally, I would disagree with that. But I’m just some Joe.
Unfortunately, it isn’t any better for Macs that have power LEDs. My 2018 Mac mini has a white power LED. And that light turns off for nearly a minute during a macOS installlation/update.
I’ve complained to Apple about this, for whatever that’s worth. It’s very bad behavior, because you can’t tell if the installation is in progress or if the system actually powered-down. And if you assume it powered down and pull the plug during this time, you could trash it in ways that may require a complete re-imaging (via Configurator).