Mac Mini 2018 Problems - Unable to Reinstall OS

Question

Mac Mini 2018 Problems - Unable to Reinstall OS

Around 18 months ago I started occasionally getting this error:

"Volume Hash Mismatch

Hash mismatch detected on volume disk1s2.

macOS should be reinstalled on this volume."

It's been functioning perfectly well and its backed up regularly so I've been putting off the reinstall.

I finally tackled it today. I used the Erase Assistant and tried to reinstall which failed so I loaded up disk utility and formatted the drive and tried to reinstall Catalina again.

The install process ran for around an hour maybe and then the Mac mini rebooted and came back with a Catalina screen saying:

"macOS could not be installed on your computer An error occurred installing macOS. To use Apple Diagnostics to check your Mac hardware, shut down, press the power button, and immediately hold the 'D' key until diagnostics begins. Quit the installer to restart your computer and try again."

So I tried to do this and now seem to be in a loop with the machine loading up to the black screen saying:

"Your computer restarted because of a problem.

Press a key or wait a few seconds to continue starting up. "

If I reboot, it gets to the point of asking me to choose a startup disk but there's nothing in the box to choose from.

I can run Disk Utility and it passes the drive with no issues.

Is this machine just completely dead? Is there a way I can get macOS back on here?

Posted on Nov 18, 2024 7:57 AM

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Answer 1

lanstrad1

Level 2

456 points

Nov 18, 2024 10:29 AM in response to Steven Taylor3

i had a similar problem (also with a 2018) few months ago: unable to update or reinstall whichever version of macOO.

Diagnostic at Apple Store was that a BETA firmware - guess how - had been installed and preventing OS update or install. I have no explanation for this as i never installed that firmware intentionnally (nor would do how to do, nor would have searched for this!)

They performed the reinstall at store and as of today never had any issue doing the updates.

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Answer 2

den.thed

Level 10

82,462 points

Nov 18, 2024 9:15 AM in response to Steven Taylor3

It's a little after the fact now, but I would have tried to re-install the macOS version that it was running over the top before wiping and starting over.

If the drive is not showing up to reinstall the macOS, then it sounds like it is not erased and formatted correctly.

see > Use Disk Utility to erase an Intel-based Mac - Apple Support

then see > How to reinstall macOS - Apple Support

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Answer 3

Nov 18, 2024 9:36 AM in response to den.thed

Thanks for the reply. I actually tried reinstalling macOS (over the top of the operating system it was already running) last year when I first had the issue. It didn't work and I've honestly lost the screen grabs of what the error was when I tried to reinstall.

Thanks for sending the links however I have already erased in Disk Utility and tried to reinstall. The method I used was the same as the links supplied.

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