Windows 10 1903 introduces Tamper Protection. Microsoft's support article is here.
Tamper Protection helps prevent malicious apps from changing important Windows Defender Antivirus settings.
Microsoft's page says "Tamper Protection is turned on by default." I didn't find that true.
To turn it on follow these steps:
- In the search box on the 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".