Windows 10: Can not install 3rd party program

Running Windows 11 Single home user. Can not install any 3rd party program. Can simply not verify the installation start. There is no option available to put in the information. Can not see the ability to allow 3rd party programs at all. I simply can not change anything that you usuallý can do as a admin. Can not even install Microsofts trouble shooting program. I would think that there is something to do with S-mode.

:)

 

3rd party AV program

The message you are describing may be observed if another antivirus program is still installed or there are remnants of a third party antivirus program still installed.

https://support.microsoft.com/en-us...b59cebc4f24/how-to-protect-your-windows-10-pc
Note the statement "If you want to use Windows Defender Antivirus, uninstall all of your other antivirus programs and Windows Defender Antivirus will automatically turn on. You may be asked to restart your device."

Go to Security and Maintenance, look in 'Security' and see what program is listed under Virus Protection. Windows Defender will not be enabled and functioning properly if there is a program other than Windows Defender listed.

For further information see the reply of quietman7 in Redirecting

You may want to try the steps recommended in Problems
starting Windows Defender in Windows 8/8.1/10 to include running SFC, scanning for malware with Malwarebytes and running the software removal tools for any security software (Avast,
AVG, McAfee, Norton, whatever) that may have previously been on the computer followed by a reboot? List of
anti-malware product removal tools

And see Configure Windows Defender in Windows
8, 8.1 and 10

If you can't resolve this issue suggest you post back in this thread and provide additional information.

Regards…

Top 10 Ways PUPs Sneak Onto Your Computer. And How To Avoid Them. - Emsisoft | Security Blog

 

3rd party AV program

I'm trying to turn-on Windows Defender and I receive a message to uninstall 3rd party AV program. How do I identify the 3rd party AV program
installed?

 

Common 3rd party programs not installing on windows 10 (adobe reader, java)

Hi,

Welcome to Microsoft Community. Your interest in Windows 10 is much appreciated.

I can imagine the inconvenience you have experienced. I will definitely help you with this.

To guide you in right direction we want to know:

• Do you get any error message?

We suggest you to download the version which is compatible with Windows 10 from the Manufacturer website. We suggest you to install the program in compatibility mode:

Follow the steps to install the program in
Compatibility mode.

• 
  Download the updated program from the manufacturer’s website.
  
• 
  Right click the installation file and select
  Properties then tap or click the Compatibility tab.
  
• 
  Place a check in the
  Run this program in compatibility mode for: box.
  
• 
  Tap or click the drop down box and select a previous operating system, then tap or click
  OK.
  
• 
  Try installing the program and check.
  

If the issue still persist we suggest you to contact the Manufacturer.

Keep us posted if you face any issues on windows in future. We will be glad to help you.