If You'll need a new app to open this windowsdefender link message appears every time you open Windows Defender, see this post.

Complete guide on how to use Windows Security (Defender) in Windows 11 to configure the maximum protection for your computer.

Where is Microsoft Defender app available and how can you use it? It’s a cross-device app, which means it is available across operating systems.

Confusingly, the Microsoft Defender app shares its name with the antivirus engine powering Windows Security’s malware protection — but they’re not directly tied.

What malware does Windows Defender recognize? Learn how to use PowerShell's Defender cmdlets to peek inside the malware signature definitions database.