Tamper Protection in Windows Security helps prevent malicious apps from changing important Microsoft Defender Antivirus settings, including real-time protection and cloud-delivered protection. If Tamper Protection is turned on and you're an administrator on your computer, you can still change these settings in the Windows Security app. However, other apps or users can't change these settings.
Tamper Protection doesn't affect how third-party antivirus apps work or how they register with Windows Security.
Tamper Protection is turned on by default. If you turn off Tamper Protection, you will see a yellow warning in the Windows Security app under Virus & threat protection.
Change the Tamper Protection setting
In the search box on the Windows taskbar, type Windows Security and then select Windows Security in the list of results.
In Windows Security, select Virus & threat protection and then under Virus & threat protection settings, select Manage settings.
Change the Tamper Protection setting to On or Off.