Could not open/load System Preferences

1 - Suggest restarting in Safe Mode. This will perform a Disk Repair, clear cache files and only load Apple Software, extensions and fonts. The boot up will be slow and can take some time - Normal.

2 - Does the issue present in this mode ?

3 - If not - there could be something in the main User Account playing up. To further isolate this - Set up users, guests, and groups on Mac. Then log out of the Main User account and log into the dummy account and test again if the issue persists.

4 - If the issue is present in the dummy account - then this appears to be a System Wide issue.

If issue persists after doing all the above please advise

User wrote " 1 & 2 - Managed to get to Safe Mode...no problem can see Display pane. - Also created a Guest User and no problem with Display pane. However, back to Main User, can see Display pane but now cannot open User & Groups pane."

The fact that in Safe Boot and the issue is not present and further verified when using another User Account indicates the issue is in the Main User Account. There is some piece of Third Party Software installed that is the cause of this issue

Unfortunately, this is not reflected in the Etrecheck Report because the user has only run the Etrecheck Application without giving it Full Disk Access.

Under these conditions - it is not possible to determine which piece of Software is the cause of your issue

Though, looking at what is available in the posted report - IMHO this computer is badly Under Powered and Equipped to run a meaningful and well performing experience on Monterey or even Big Sur

The biggest impediment  and cause of most of this computers issues is the Hardware.

The computer has only 4 GB RAM which cannot be upgraded. For a reasonable  performance on Monterey or Big Sur would need at least 8 GB RAM and 16 GB RAM for even better performance.

APPLE HDD HTS545050A7E362 500.11 GB (Mechanical - 5400 RPM) This also is a Major Factor to the overall performance.  No matter how clean the Operations System is kept and no matter what Third Party Software is installed - this drive will alway struggle to keep up with the demands placed upon the computer 

Hardware Information:

Mac mini (Late 2014)

Mac mini Model: Macmini7,1

1.4 GHz Dual-Core Intel Core i5 (i5-4260U) CPU: 2-core

Performance: Below Average

Problem: Computer is too slow Description:

Q - No Time Machine backup - Time Machine backup not found.

A - A Time Machine Backup  is very useful and can be used to Revert to Previous Working macOS.

Low performance - EtreCheck report took an unusually long time to run.

Q - x86-only Apps - This computer has x86-only apps might not work on future versions of the operating system. 

A -  There would be more meaningful information provided should the Full Disk Access Report  posted.

A- Limited drive access - More information may be available with Full Drive Access.

So it appears from you reply that there is something in the User Account ( Main ) which is playing up.

To better see what it might be >>

Suggest downloading the Application Etrecheck directly from a well Respected ASC Contributor. And Safe to use.

The application is free or paid from added features. 

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 )

We can have a look at the report for possible issues and may have possible suggestions to resolve the issues.

Any Third Party Applications that will interfere with the normal operation of the OS, alter, modify, remove or delete or attempt to do so is an invitation for disaster and may require a Reinstallation of the OS.

Any of the below should be removed as per Developers Instructions 

This includes AntiVirus, Disk Cleaners, Disk Optimizes, UnInstaller etc.

This will include CleanMyMac , This will include BitDefender , 

This will included Norton Antivirus , Sophos Av Software

Intego AntiVirus, McAfee, MacKeeper, Avast AntiVirus

Ad Guard, Webroot

The The Built in Security  is all that is required.

Suggestion, get a more capable computer with more RAM and a SSD Drive large enough for your computer needs.

The 2014 Mac Mini just qualifies for Monterey macOS 12.

This machine will probably not make the qualifying list for anything newer come the summer or fall of 2022.

It would not all the upgrade to Monterey if the computer did not qualify.

The point remains, running the latest version of MacOS on an 8 year old computer with only 4 GB RAM and the slowest Rotational HD and factor in the " kvms pro hardware version: V1.0 not supported " is going to have issue.

Then, we add in the Non Full Disc Access of Etrecheck Report and presto - we are not able to define just what and where the Software issues may be.

Reviewing the Report and will be back to you shortly

Looking at the report now and will get back to you

kvms pro hardware version: V1.0 not supported

Ok but still goes not address the issue of the lack of RAM and SSD Drive for Monterey Performance issue