SystemUIServer uses 100% CPU

This can be due to some misbehaving agent or daemon.

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

Antivirus software: Apple, CleanMyMac, and CrowdStrike

Part 1 of 3

Once this types of software is installed and embedded into the computer 

You can spend hours or days hunting down all the bits and pieces of this software and never really get it all off the computer 

Start Over from Scratch 

For Apple Silicon computer >> Use Disk Utility to erase a Mac with Apple silicon.

For Apple Intel computers >>   Use Disk Utility to erase an Intel-based Mac followed by How to reinstall macOS

Always make a Time Machine Backup  before  proceeding 

If going this route - I suggest Not using Startup Assist to migrate everything back.

This will probably Re-Introduce ( CleanMyMac, and CrowdStrike ) back into the Operating System 

Part 2 of 3

CleanMyMac , aka “ BrickMyMac “

Part 3 of 3

There are no known Windows-like Viruses in the wild that self replicate and affect macOS, because of the underling UNIX  Foundation and Permission Limitation. 

The Operating System resides in a Sealed and Read Only Volume that cannot be opened by the User nor by Third Party Applications.

The Only thing this Antivirus software is protecting is the Bank Account of the Developers and for zero return to the User aside from the problems this software creates.

AntiVirus Developers purposefully Market their product to create a “ Fear Factor “. In so doing, creating a False Need for their Product.

Security. Built right in

Mac app security enhancements

 The Built in Security  is all that is required to protect the computer.

Protecting against malware in macOS

There is Adware & Malware which will affect the computer and is generally downloaded from “ Shady “ Websites or Developers who Inject this software into the download.

From a well written User Tip from @Kurt Lang

https://discussions.apple.com/docs/DOC-2500088

Shmulik-m wrote:

Thanks for the comments. I expose my ignorance... can anyone tell me what to do in simple non-professional language?

This appears to be a mac issued by your organization, and "managed" means that the IT imposed some restriction on what the user (you) can do.

Thus the way forward is to contact your IT department, report the problems and ask them to make the necessary changes.

That's a managed device. You may need to ask your IT admin support to make changes.

The primary problem is that ancient SIMBL hack. It's crashed 479 times in the past few days.

You can use the Activity Monitor to see what is using the various resources like, CPU, Memory, Energy, Disk, & Network. You can click on any one of those column heading to sort by ascending or descending as needed.

Use Command + Spacebar to open Spotlight then type in, Activity Monitor to open it from there.

I think the best answer comes from @Luis Sequeira1

Just be sure to mention to the IT Department that the infamous CleanMyMac Application has been used on this computers

With that piece of Info in had, the IT Department may take a slightly different tact / approach to fixing the computer

You sever different anti viruses in your system! Delete one of the, to start with! Also have tried /Applications/Utilities folder/Activityy viewer and find the service that is out of control and then delete it and replace it!

I am somewhat surprised a Managed Computer would allow the BrickMyMac to be installed and used on this machine

But , I guess anything is possible these days