[hsbauauvhabzb]

Because working in security sometimes I want to test malware on outdated AV, blocking full internet causes command and control failures, creating a weird spot to analyse traffic. Disabling Defender is not persistent (it seems to switch itself on, etc).

[WolfRazu]

If you disable defender using group policy, from my experience that's been disabled consistently for a year no problems. Latest version of Windows 10.

Note you need to disable tamper protection and reboot first otherwise it silently reenables itself.