アプリ版Microsoft Defenderの自動インストールが開始。好むと好まざるとにかかわらず - ニッチなPCゲーマーの環境構築Z

https://www.nichepcgamer.com/archives/microsoft-defender-app-ver-automatically-install.html
Installing Microsoft Defender

Important: This article is about the Microsoft Defender app that is included with Microsoft 365 Family or Personal subscriptions. If you're looking for information about the Microsoft Defender Antivirus that is built into Windows, see Stay protected with Windows Security.


If you don't have an active Microsoft 365 subscription right now

• Open https://aka.ms/WindowsDefender to go to Microsoft Defender in the Microsoft Store and select Install.
• After installing, sign in with the personal Microsoft account (such as @outlook.com, @hotmail.com, or @live.com).

family organizer がまだ Microsoft 365 利用していないんだけどな
試してみよう

追記

Windows セキュリティはそのままで変わらない
マイカスペルスキーみたいなもんか