Microsoft Defender Antivirus is the default antivirus solution for the Microsoft Windows 11 operating system. It is turned on by default unless other security solutions recognized by the operating system are installed. Previously, it was called Windows Defender. Most third-party antivirus solutions that support Windows 11 are recognized, but there are cases where third-party antivirus software doesn't.
Windows 11 users are advised to keep Microsoft Defender Antivirus turned on if no other security solutions are installed. But due to some reasons, such as Windows Defender Antivirus causing high resource usage or other problems with the system, or users testing software with Windows 11's virtual machine, in this case, users may want to temporarily or permanently turn off Microsoft Defender Antivirus. Next, we'll walk users through how to enable or disable Windows Defender.