How to upgrade previous version of macOS, e.g. BigSur

tuulikki176 wrote:

Hi,

as new upgrade, Monterey, is not working properly, is there any possibility to upgrade previous version, e.g. BigSur?

Br, Tuulikki

Revert your Mac to a previous macOS version
https://support.apple.com/en-lamr/guide/mac-help/mh15216/10.15/mac/10.15

How to erase your Intel-based Mac - https://support.apple.com/en-us/HT208496

How to reinstall macOS from macOS Recovery - https://support.apple.com/en-us/HT204904

If necessary you can download the old installers—

verify you are using the Safari browser to download/initiate the macOS links.

The older macOS installer backups on this server:

https://support.apple.com/en-us/HT211683

Be aware - the following method will WIPE ALL DATA and there is no Recovery - period.

USB Installation & Wipe and Install

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

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 Big Sur would have to be done on a computer that Qualifies to run Big Sur.

Once that is done read on for preparing the Destination computer  >>

Only works on Intel Based Apple Computers.

Extra Special Notation regarding the Touch ID equipped Apple Computer. About Startup Security Utility and Must Enable from Recovery Mode the ability to boot from External Drive Before Attempting 

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

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

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

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

5 - 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. 

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

7 - Follow the prompts and it may automatically reboot several time. 

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

I do know, the first release of Monterey version 12.0.1, there will almost certainly be a number of " corrections ".

Normally - when bugs in Monterey are found and enough have been fixed - Apple will release updates for Monterey.

As example - Big Sur was released as version 11.0. and followed by 11.0.1 and several more updates until the latest version Big Sur 11.6.1.

We should expect a similar progression for Monterey

What's wrong with your Monterey upgrade?