MSE was preinstalled on Windows 7 (as an optional download) and became the default antivirus for many home users. However, as cyber threats grew more sophisticated, MSE struggled to keep pace. Independent tests from AV-Comparatives and AV-Test consistently showed MSE lagging behind competitors like Bitdefender, Kaspersky, and even the free edition of Avast.
Note: Any third-party antivirus will automatically disable Microsoft Defender’s real-time protection to avoid conflicts. microsoft security essentials windows 11
This article explains why MSE is incompatible with Windows 11, what replaced it, and how to ensure your system stays secure. MSE was preinstalled on Windows 7 (as an