How to check a Windows PC for malware using Microsoft Defender

Identifying Malware Symptoms

Modern malware often operates subtly to avoid detection, unlike older forms that caused obvious pop-ups. Users might suspect malware if their PC experiences sudden slowdowns, frequent freezes, or unusual processes running in the background. These symptoms indicate a need for a thorough security check.

Starting with Microsoft Defender

Windows 11 includes Microsoft Defender as part of its Windows Security suite, which is enabled by default and performs regular scans. The Virus & threat protection section within this suite is the primary area for managing malware scans. Green checkmarks indicate a healthy system, while yellow or red icons signal concerns.

Understanding Scan Options

Microsoft Defender offers various scan types. Quick scans focus on common threat locations, while full scans examine all files, which can take considerable time. For deeper analysis, the Microsoft Defender Antivirus (offline scan) restarts the PC into the Windows Recovery Environment, allowing it to detect malicious threats that attempt to hide during normal operation.

Reviewing Protection History and Firewall

Users should check the 'Allowed threats' section to review any flagged items they have approved; unrecognized entries here could indicate a problem. The 'Protection history' tab logs all actions taken by Windows Defender. Additionally, it is important to ensure the firewall is active for all connection types within the Firewall & network protection settings to block unauthorized incoming connections.