[Resolved]Updating from Mojave to Big Sur, errors/unfinished update?

[perdja]

In another thread I was struggling with getting the EFI correctly setup and a boot file in root preventing parts of the installation process.
Now having all that in place I started upgrading my Mojave installation to Big Sur. I have made several attempts with reformatting of destination disks and restoring from backup before upgrade attempt in order to have the same preconditions but I seem to end up in an incomplete, yet partly functional, installation of Big Sur.

Indications in Big Sur:

• I have dual Preferences. The one I get from Apple menu is Mojave and cant be accessed e.g. for Security settings. The Big Sur is available from Spotlight search and works generally for settings. However, settings relating to allowing apps, e.g. Audio Hijack, does not work as advised. Also all default system apps delivered with OS have both Mojave and Big Sur versions still available i Applications folder
• I need to make xattr -cr commands in Terminal to be able to install any downloaded dmgs work. Getting a "corrupted.." message if I do not xattr the downloaded files. This also means that stuff that needs to be installed that doesn't end up in a dmg, e.g. CommandLineTools, can not be installed at all
• Applications with usb dongles (Cubase, Dorico) work flawlessly
• Lock screen is Mojave even though system version is 11.1

So there seems to be some incompleteness in the install. Having done the installation several times now I know there are two startovers where the OSInstall partition is used and then I executed have variants of the install when the system starts up configurating the third time either from the HD-Data partition being created or from the HD. In the first case (-Data) the result ends up with just Mojave again and this is the option the installer seems to default to. Forcing startup the 3rd time on HD partition ends up in Big Sur but with indicated anomalies as above.

Will resort to a clean install and reinstall all apps, but if anyone out there has a clue where I go wrong and suggestions how to do it right, I'll will appreciate any suggestions for sure.

 

[perdja]

It turned out that a clean install was the only way I could get things working. This was not too bad as I also found the migration tool which transfered user and settings without problem. There seems to be too much going on regarding security improvements in Big Sur to handle it the upgrade way.

I had one final issue and that was that the user that I transferred could log in to the computer but could not use the password to make changes in System Preferences. I saw that this has been an issue with other based on google finding. But I did not have to use the Recovery/Terminal method which was described. As I had a user which was created during installation process, I used that admin to delete my imported user (while not deleting home catalogue) and then re-created that user following the steps here. This set the authorisation straight on the imported account. All good!