Unable to upgrade macOS on iMac 2020 after factory reset

Question

Level 1

4 points

Unable to upgrade macOS on iMac 2020 after factory reset

I have iMac 27" 2020 computer. After erased and reset it to factory settings, I can't upgrade Catalina macOS to newer version. I tried upgrade to different macOS. I even tried to install it on exterior ssd, without success. Every time I tried, everything was going smooth until 14 minutes left to install. At this point I got message "An error occurred loading the update". Every time I install update, I got this message at magic 14 minutes. Am I doing something wrong, or is some hardware problem. I've run etrecheck.com and everything was fine, no problem detected. I erased HD many times but nothing change, 14 minutes and installation is stoped. Maybe someone knows, what is the problem and can help me with this issue.

[Re-Titled by Moderator]

iMac 27″

Posted on Dec 11, 2024 11:23 AM

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Answer 1

Owl-53

Level 10

111,171 points

Dec 12, 2024 4:56 AM in response to domczes

Scorched Earth Method

This method will WIPE ALL Data and there is No DATA Recovery - Period.

To perform this action will require booting from a Bootable Installer.

The Bootable Installer can Only be performed on an Apple Computer

This will have to be performed from a Qualifying Computer to run the version of macOS to be made on the Bootable Installer.

Example : Bootable Installer of Sequoia would have to be done on a computer that Qualifies to run Sequoia .

Notation: If the computer being used to perform this action is Too New or Too Old to qualify to run the version of macOS - this computer can’t be used.

Alternative is, to gain access to a Qualifying Apple Computer from a family member, friend or associate.

Shutdown computer and disconnect all external drive >> Except the newly created Bootable Installer.

Restart and immediately hold the OPTION key until the Startup Manager appears and choose the USB Drive.

It will present options >> Disk Utilities >> View >> View ALL attached Drives.

Choose the Upper Most Drive ( not the volumes indented and list below ).

The drive normally is called Apple Media or Apple SSD - that is the drive to Erase and format as APFS with the GUID Partition Map.

Once that is done >> backup out of Disk Utilities and choose install macOS.

Follow the prompts and it may automatically reboot several time.

Upon a final reboot - Setup Assist will present with the newer version of macOS.

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Answer 2

Owl-53

Level 10

111,171 points

Dec 12, 2024 3:38 AM in response to domczes

Try Turning OFF FileVault

This may take some time so be patient

There seems to the be something of concern here

The Internal Drive is reported as APPLE SSD AP1024N 1.00 TB

But below is reporting a 2.15 GB Shared Values which could be an issue

Plus, that 2.15 GB Is formatted in macOS Extended Journaled

Is the computer using an External Drive or the Internal Drive to run the Operating System

Encrypted Used: 2.15 GB Shared values

Size: 1.00 TB Free: 952.24 GB

disk1s5 - Macintosh HD Filesystem: APFS Mount point: / Encrypted Read-only: Yes Used: 11.18 GB Shared values

Size: 1.00 TB Free: 952.24 GB

disk2s2 - S************t

Filesystem: Mac OS Extended

Disk Image

Mount point: /Volumes/S************t Read-only: Yes

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Answer 3

Owl-53

Level 10

111,171 points

Dec 12, 2024 1:38 PM in response to domczes

If an error occurred while updating or installing macOS - Apple Support

Check your internet connection

Operative Wording >> The installer needs a stable internet connection to get firmware and other information specific to your Mac. Make sure that your Mac is connected to the internet.

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Answer 4

Owl-53

Level 10

111,171 points

Dec 12, 2024 1:11 AM in response to domczes

Perhaps we can spot something that is causing this ongoing issue

Post back the Full Report - copy and paste - >>>> using the Additional Text Icon <<<<

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Answer 5

Owl-53

Level 10

111,171 points

Dec 13, 2024 7:49 AM in response to domczes

To possibly remove any possible oversight

If you would provide a screen shot from > > " About this Mac " without the Serial Number appearing

Sorry, but sometimes a computer purchased in 2020 is really not a 2020 iMac ?

Aside from that >>

Have the computer evaluated by the Professionals who have the Special Hardware Software and Expertise to diagnose the issue and offer possible solutions

Make an Appointment at the Apple Genius Bar or call 1 800 MyApple and have them evaluate the computer

Other location Call Centres

Contact Apple for support and service

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Answer 6

domczes Author

Level 1

4 points

Dec 12, 2024 2:59 AM in response to domczes

First, I opened macOS Utilities. Second, I erased Macintosh HD using Disk Utility. After that 
I reinstall macOS Catalina. Than I run Safari and some security update. When Catalina was
working fine, I run Sequoia upgrade. Upgrade was doing good until 14 minutes of installation left. 
At this point I got message '"An error occurred loading the update". I decided to download 
EtreCheckPro to check my mac. Report said, everything is ok. 
I did check just after upgrade failed,that mean, no 3rd party software should be on my computer.

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Answer 7

domczes Author

Level 1

4 points

Dec 12, 2024 4:42 AM in response to Owl-53

Thanks for your response. My FileVault is off, I never turned it on. Looks like every time I tried to upgrade, software was adding another Macintosh HD.

Because of unsuccessfully upgrades, at one point I tried to install Sequoia on external drive. Which was unsuccessful either.

Everything what I did, was erasing HD, reinstalling macOS Catalina, update Safari and Catalina security files. After that, I tried Sequoia upgrade.

If anything is wrong, Mac was doing it by itself.

Now is the question, what I can do to completely erase Macintosh HD and rid off of all unnecessary things?

Another thing its, I put Mac to factory reset, because Mac was restarting very often by itself. Unfortunately, Mac still doing this sometimes.

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Answer 8

domczes Author

Level 1

4 points

Dec 12, 2024 10:54 AM in response to Owl-53

Thanks for your advise. I did exactly as you said, unfortunately I got same message at exactly same time.

It's very funy because Catalina is working but anything else, won't work. I have to upgrade from Catalina because with this macOS I can't even install Google Chrome. I don't know what's wrong with this computer.

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Answer 9

domczes Author

Level 1

4 points

Dec 13, 2024 7:31 AM in response to Owl-53

This is not the point. I have Fiber Optic and stable connection. If internet will be the problem, all upgrades i was trying to do , probably will end at different times. All upgrades ended exactly at 14 minutes left of installation. That

must be different kind of problem.

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