Unable to update my mac

macOS Big Sur is compatible with these computers - it this computer appear on this list - it Qualifies for Big Sur.

How to upgrade to macOS Big Sur and be sure to check the Empty Space Requirements -i f upgrading from macOS Sierra or later, your Mac needs 35.5GB of available storage to upgrade. If upgrading from an earlier release, your Mac needs up to 44.5GB of available storage. To upgrade from OS X Mountain Lion, first upgrade to OS X El Capitan, then upgrade to macOS Big Sur.

Worth Reading Before attempting the upgrade to Big Sur >> Tips How to Upgrade to Big Sur 

Etrecheck is a diagnostic utility that you can download for free. It was created by frequent contributor so that users trying to help here can look at the report and be able know enough about your setup to better assist. As you can see for yourself before posting, the report does not contain any private information but will let us know stuff like the OS version, recent crashes and most importantly third party software modifications that may be causing problems.

Would be even better if the Report was with Full Disc Access. This is only a partial report and as such can only give partial support.

 Run the application with Full Disc Access ( Security & Privacy - Full Disc Access ). It will take a Snap Shot -  both the hardware and software. The Report will Not Reveal Any Personal Information. Post back the Full Report - copy and paste - using the Additional Text Icon ( 3rd Icon to last )

You have this thing "cososys.epp" which appears to be some sort of "public vpn".

This on one hand is old and on the other hand probably a bad idea.

You may read up on this excellent post:

Public VPN are anything but private

I would try uninstalling and see how things go.

P. Phillips wrote:

@Luis S - Noticed UnBalanced RAM - Bank 0 - No RAM Installed and Bank 1 - 16 GB RAM. We know apple hardware software is very picky about such things. Thusly the Update / upgrade is kicking OUT

Maybe, but I don't think it's likely. There can be a small benefit from balanced RAM, but AFAIK it has not been required in recent years in any mac.

Then, answered in previous posting. Just, please take the time to read the links supplied above.

First of all, why cannot you update to Catalina 10.15.7.

What happens when you try.

A 2018 Mac Mini can upgrade to macOS Big Sur, have you tried!!!

You can try updating while running in Safe Mode.

Also, Please run Etrecheck and post its full report here. Use the "additional text" button and paste the report into the text box.

@Luis S - Noticed UnBalanced RAM - Bank 0 - No RAM Installed and Bank 1 - 16 GB RAM. We know apple hardware software is very picky about such things. Thusly the Update / upgrade is kicking OUT