How to check if Microsoft Defender is working in Windows 11
Learn how to verify Microsoft Defender Antivirus protection in Windows 11, what real-time protection means, and how Sentinel AI fits alongside Defender.
Start with Windows Security
Open Windows Security from the Start menu and choose Virus & threat protection. Windows shows current threats, recent scan information, security-intelligence status, and the controls for Microsoft Defender Antivirus.
To verify the active antivirus provider, open Virus & threat protection and look under Who’s protecting me? / Manage providers. If Microsoft Defender Antivirus is your active provider, verify that Real-time protection is on under Virus & threat protection settings.
What real-time protection does
Microsoft describes real-time protection as continuously monitoring files and programs as they are accessed or executed. That antivirus function belongs to Microsoft Defender—not Sentinel AI.
Why security status is only part of the picture
Knowing that antivirus is enabled answers one important question, but it does not by itself explain unusual processes, unexpected network activity, persistence mechanisms, startup behavior, or the history of an investigation. Those broader questions are where Sentinel AI is designed to add value.
Where Sentinel AI fits
Sentinel AI is a Windows security suite built around continuous monitoring, investigation, evidence correlation, containment, quarantine, remediation, optimization, and clear guidance. It works alongside Microsoft Defender rather than replacing the antivirus engine. Defender remains responsible for antivirus and antimalware scanning; Sentinel adds the broader investigation and response workflow around Windows system and security evidence.
View Sentinel AI in Microsoft Store
Frequently asked questions
Does Sentinel AI replace Microsoft Defender Antivirus?
No. Microsoft Defender remains the antivirus and antimalware engine. Sentinel AI works alongside it with broader monitoring, investigation, containment, quarantine, remediation, and evidence-grounded guidance.
How can I see which antivirus is protecting Windows?
Open Windows Security, choose Virus & threat protection, and use Manage providers under the protection-provider section to see the active antivirus provider.
Should I turn off Defender to use Sentinel AI?
No. Sentinel AI is designed to work alongside Microsoft Defender and Windows security protections.
Last reviewed: September 6, 2026.
Check whether Microsoft Defender is working: practical checklist
Windows Security reports protection status, but a green icon is only one signal.
Start with a clear first step
Open Windows Security from Start and review Virus & threat protection, protection updates, and protection history. Look for alerts that require attention, and check whether real-time protection is enabled.
Check the context before acting
If a setting is managed by your organization, do not attempt to override it. Ask your administrator. If protection is disabled unexpectedly, investigate why before installing additional tools.
What to do next
Defender and a monitoring product serve different purposes. Defender supplies antivirus protection; Sentinel AI is intended to help review suspicious behavior and investigate signals, not replace Defender.