MacMini fails to reboot after sw update

[Airscrew]

Hi All,

New to me yesterday, MacMini 2018.
System refreshed by previous owner.
Booted fine and went through setup, language, user, pw etc, all OK (done this before on another MacMini)
It found and suggested a software update (was 14.7), agreed yes, updated ok with no interruptions, and then started to reboot in the usual way, but just hung on the Apple logo screen
Waited many minutes, but nothing...

Tried to start with the on/off button...
No startup 'chime'
Black screen with the text
<<Your computer restarted because of a problem. Press any key or wait a few seconds to continue startup>>
Then moves to the apple logo and the loading bar, which progresses about halfway, then turns off completely.
Repeatedly.

Its a MacMini, 2018, so using a wired USB keyboard (windows) just for the setup.
But I cant get it to enter recovery with the keyboard with either Option R or Command R

How do I force it into some sort of recovery mode.?

What other options do I have?

If it helps, have a full and recent Time Machine backup from my exiting MacMini 2012 machine v.10.15.8 (using to type this)


All suggestions appreciated - Jon

 

[bogdanw]

Try the steps for "Desktop computer with the T2 chip"
https://support.apple.com/en-us/102605
"Desktop computer with the T2 chip
If your Mac isn't a laptop computer, follow these steps:
Shut down your Mac, then unplug the power cord.
Wait 15 seconds, then plug the power cord back in.
Wait 5 seconds, then press the power button to turn on your Mac."

And
"If you can’t start up from macOS Recovery (Intel-based Mac)
To help ensure that your Mac can recognize the keys you’re pressing at startup:
If you’re using a Mac laptop, use its built-in keyboard instead of an external keyboard.
If you’re using an external keyboard, you might need to wait a few seconds before pressing any keys to give your Mac time to recognize the keyboard as it starts up. Some keyboards have a status light that flashes briefly when the keyboard is ready to use.
If you’re using your keyboard wirelessly, plug it in to your Mac, if possible. Or try a wired keyboard.
If your keyboard is made for PC, such as one that has a Windows logo, try a keyboard made for Mac.
If your Mac tries to start up from its built-in Recovery system but can’t, it should automatically show a spinning globe as it tries to start up from Recovery over the internet. Or you can force Internet Recovery by pressing either of the following combinations at startup, instead of Command-R. (Each combination also affects the version of macOS offered when reinstalling macOS from Recovery.)
Option-Command-R
Shift-Option-Command-R
If the spinning globe includes a warning symbol (exclamation point), startup from Internet Recovery was unsuccessful:"
https://support.apple.com/en-us/102518

 

[Fishrrman]

First -- do you have another keyboard you can try?

Have you installed anything of your personal software onto it yet?
Apps, accounts?

REASON WHY I'm asking: makes a difference whether you want to wipe it all (erase the drive and start over), or just re-install the OS.

What I'd try next:
Power down, all the way off (you're probably there already).
Press hold, and DO NOT LET GO of Command+Option+R, and touch the power on button.
Keep holding those keys down.

You can let go when either occurs:
a. you're asked to enter your wifi password (connecting via wifi)
or
b. you see the spinning globe (connected via ethernet).
Ethernet is better if you have it available.

You're booting to INTERNET recovery (NOT "the recovery partition).

When you see the internet utilities panel, you have a choice.
You can either:
a. erase the entire drive and start completely over
or
b. reinstall only the OS

If you want to re-install the OS, open the OS installer and start clicking through.
I would accept whatever version of the OS you are offered.

If you want to erase and start over, open disk utility first.
IMPORTANT: go to the "view" menu and choose "show all devices".
Now you can see the internal SSD as "the top item" in the list on the left.
Click that.
Erase to APFS, GUID partition map.
When done, close disk utility and open the OS installer, and go on from there.

When the OS install is done, connect your time machine backup when you see the "choose your language" screen.
At this point you can either "set up fresh" (new account, etc.), or connect your backup and use setup assistant to migrate everything over.

Good luck!

 

[Airscrew]

Thanks to you both, Fish and BogD,

I left it fully off overnight, tried a different and old keyboard (checked it worked), and it seemed to have reset the PSU.

Then CommR worked and rebuilt the existing OS, and then the full upgrade to 15.7.7.
Then the migration tool, and my old setup is now fully across onto the newer MacMini.
Yay!!

I really appreciate the followup. Thanks.