Boot Problem with 2019 Refurb iMac

[DonP]

I just purchased a refurb 2019 27" iMac from the Apple Store. I unboxed and it booted up to Mojave, so I began Migration Assistant from my 2009 24" iMac running El Cap. Migration took two hours over wifi and new iMac booted up looking just like my old iMac. I had to reinstall a few apps that didn't migrate over but I seemed to be good to go after a few trouble free reboots.

On the last reboot the iMac hung with the Apple icon and progress bar at 100% but frozen for hours. Apple telephone support spent an hour with me troubleshooting and trying various startup scenarios but it always freezes without completing. They finally gave up and made a Genius Bar appointment for me on Saturday.

Is there anything else I could try before the Genius Bar? At this point I can't even do a fresh install of Mojave and start over. Not sure if this is a hardware issue, software issue, or something about the file migration. Ten years with the 24" iMac and never a problem like this with a hard freeze. Thanks for any suggestions.

 

[Fishrrman]

Can you boot in safe mode?
(hold down shift at startup)

Can you boot to the recovery partition?
(command-R at boot)

Can you boot to INTERNET recovery?
(command-OPTION-R at boot, wifi password needed)

If none of these work, take it to the Genius bar.

 

[DonP]

No to all, so Genius Bar is next.

 

[komatsu]

well, did they fix it?

 

[DonP]

Genius Bar appt is on Saturday so I haven't been yet, but the situation has changed.

Originally I spent an hour with Apple phone support and we tried, swapping keyboards, power cycling, several key combo on boot, none of which worked:

hold down shift at startup
command-R at boot
command-option-R at boot
command-option-P+R at boot

The next day I again tried to boot to recovery partition (command-R at boot) and it booted up to a "macOS Utilities" screen. From there I command-q to quit to Restart. At this boot up, in small text below the progress bar, a time of "38 minutes" was indicated for boot to complete, which actually took about 10 minutes to reach the normal user login screen. Since then everything appears perfectly normal and no further issues so far. I can reboot and nothing freezes.

I called Apple support again today to close the ticket and cancel the Genius appt. Support had no theories about what happened and no interest in checking anything further. So what exactly happened is a mystery to me but I seem to be good to go now. The upgrade to Catalina will be a clean install which is probably long overdue.

 

[loekf]

Sounds like... some file system corruption ?

However, AFAIK iMacs never by itself attempt to fix file system errors.

File system hell I've seen once when a 21" inch 2013 iMac complained about file system errors during an OS X/macOS update and the only way out was recovery, wipe, re-install. My sister upgraded to a SSD iMac last year and it has been my suspicion the HDD was bad from the beginning (that machine was very slow, but just bearable).

 

[Fishrrman]

First, a question:
Do you have "automatic software updates" turned ON ???

That may have been the center of the problem.
You might have gotten "halfway through" an automatic OS update, and then... something went wrong.
And from that point... trouble.

My advice for the future:
IF you have automatic updates turned on, TURN THIS ALL OFF.
You DO NOT WANT "updates behind your back".
At least, I don't.

Notify me that an update is available, yes.
But... I'll install it myself.