If Micosoft Defender does not turn off even when you have installed 3rd party AntiVirus, then learn how to turn off Windows Defender.

5. Click Windows Components, and then select Microsoft Defender Antivirus. 6. Scroll down to the bottom of the list and look for Turn off Microsoft Defender Antivirus.

How to turn off Windows Defender’s enhanced notifications in Windows 10 Windows Defender in the Anniversary Update loves to tell you what it's doing. Here's how to stop that.

Warnings Permanently turning off the Windows Essentials or Windows Defender program without activating another anti-virus program will leave your computer vulnerable to attack from malicious software.