Spaces Previews in Mission Control are not displaying opened windows and apps

I'm under the impression that I have an application installed that is messing with Mission Control,

<Avira Security.app> Third party AntiVirus is not recommended— it typically does nothing but add issues to the macOS and competes directly with Apple’s own built in security

< CleanMyMac X.app> this app is as close to malware as you can get— i would look for some in app official uninstaller

if in doubt search the developers website or contact their: Support/Help/FAQ/Known issues/compatibility/updates…

Contact a third-party vendor - Apple Support

Contact a third-party vendor - Apple Support

Uninstall all third party apps that are Cleaners/Optimizers/VPN/Anti-Virus

all known to cause issues on the macOS

lucianoarguello wrote:

I found the root cause. It's MacWhisper. I closed the app and BUM! Problem solved.

MacWhisper is so buggy it creates almost as many problems as it solves.

Good computing lucianoarguello ! Appreciate your feedback here.

The current stable release of Sequoia including bug fixes, security updates is macOS 15.6.1

Keep your Mac up to date - Apple Support

Keep your Mac up to date - Apple Support

I second the assessment provided earlier 

There are two avenues available to address these issues

One of which has been already suggested 

The other is, 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 

Emphasis on User Account Only

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

This will probably Re-Introduce ( Avira and CMM ) back into the Operating System . 

1 - Third Party Security Software >>  Avira ,

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.

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

2 - Third Party Disk Cleaners / Optimizer  >> CleanMyMac , aka “ BrickMyMac “

Any Third Party Applications that will interfere with the normal operation of the OS,  is an invitation for disaster. 

Certain Applications maybe available on the Apple Apps Store - this only means the Developer is prepared to pay Apple a percentage on each sale. 

What the Application may do to the computer is up to the User to check this out before purchase

To put the Third Party Disk Cleaner / Optimizer in context and the damages it may have or has already done.

This type of applications can or will Muck Up your User Account ( Home Folder ) of this machine.

It does not touch the Operating System itself unless you consider your User Account ( Home Folder ) as part of the Operating System.

The Operating System is hosed