Problems with Big Sur "upgrade"

Tio_Ricardo Said:

"Problems with Big Sur 'upgrade': After 'upgrading' to Big Sur on my iMac I am having multiple problems, the most frustrating being a duplicate set of System Preferences, one functional and clearly appropriate for Big Sur and the other dating from three years ago.[...]How do I eliminate or disable the older app that keeps reloading on each new start? Thank you for any suggestions."

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Two Thoughts:

What to consider performing, in the order provided:

A. Restore from a Backup:

Do you have a Time Machine Backup of your Mac that you create prior to this? If so, restore form it. If not, take this as a learning experience, knowing to always create a Time Machine backup of your Mac prior to making any major change to is (i.e. macOS upgrade), so that you can have something to restore your Mac from, should anything go wrong with the upgrade.

B. Reinstall the macOS:

Why a Reinstall:

If you reinstall the macOS, nothing would be deleted. All intended, original files and Apps that came on your macOS would be reinstalled (which includes the Finder GUI). It’s all about keeping your system files intact.

Important: Prior to the reinstallation, create a Time Machine Backup of your Mac, so that you can have something to restore your Mac from, should anything go wrong, doing the install.

Tio_Ricardo Said:

"Problems with Big Sur 'upgrade': Dear Littles: Thank you for your kind reply. The backup was not my problem, and your solution is sensible. I was simply curious as to why older applications were appearing and becoming the preferred system files. I am sure you can tell me, but I guess I am not that curious. I have begun to solve the problems simply by tracking down the various errant older duplicate apps and moving them with their associated folders to the trash.[...]"

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Why Risk a Dead Install:

Seems fiddling with the system files would cause issues here. I am not certain as to whole apps would be duplicated, butter here is what to do...

The Ultimate Solution...

Reinstall the macOS Anew:

I. If it applies: Back up your Mac with Time Machine - Apple Support

Then...

II. Reinstall the macOS Anew:

1. Boot: into Recovery Mode.
2. Open: Disk Utilities
3. Delete: the partition
4. Reinstall: the macOS

Once Installed Anew...

III. Reinstall All the Software:

1. Use Migration Assistant to move Apps a Files back in.
2. Ask developers for new software keys - but contact the developers only --- none other --- or you may end up with malware and spyware installed.