Enabling antivirus on Windows 11—typically in the form of Microsoft Defender Antivirus—is an essential step to ensure your system remains protected from malware, ransomware, and other online threats. Windows 11 comes with Defender enabled by default, but if you’ve disabled it or need to ensure it’s active, here’s how you can do it: Method 1: Using Windows Security This is the most straightforward way to ensure your antivirus is active. Open Windows Security: Click the Start button and type Windows Security, then select the app from the results. Alternatively, press Windows + I to open Settings, then navigate to Privacy & security > Windows Security and click Open Windows Security. Access Virus & Threat Protection: In the Windows Security window, click on Virus & threat protection. Enable Real-time Protection: Under the Virus & threat protection settings section, click on Manage settings. Toggle Real-time protection to On. You can also ensure that Cloud-delivered protection and Automatic sample submission are enabled for additional security. Confirm Activation: Once toggled on, Defender should actively monitor your system. You can run a quick scan from the Virus & threat protection screen to verify it’s working. Method 2: Using Group Policy Editor (for Pro, Enterprise, or Education Editions) If you’ve previously disabled Defender via Group Policy settings, follow these steps: Open Group Policy Editor: Press Windows + R, type gpedit.msc, and hit Enter. Navigate to Defender Settings: In the Group Policy Editor, go to: Computer Configuration > Administrative Templates > Windows Components > Microsoft Defender Antivirus Adjust the Policy: Find the policy named "Turn off Microsoft Defender Antivirus". Double-click the policy and set it to Not Configured or Disabled. This tells your system to keep Defender active. Click Apply and then OK. Restart Your Computer: A restart will help ensure the changes take effect. Method 3: Using Registry Editor (for Windows 11 Home) If you’ve disabled Microsoft Defender by modifying the registry, you can re-enable it by editing the registry. Proceed with caution and back up your registry first. Open Registry Editor: Press Windows + R, type regedit, and hit Enter. Navigate to the Defender Key: Go to: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender Modify the Disable Flag: Look for a DWORD value named DisableAntiSpyware. If it exists, double-click it and change the Value data to 0, or delete the value to let Windows revert to default protection settings. Restart Your Computer: This will apply the changes and reactivate Microsoft Defender. Diagram: Overview of the Process plaintext [Windows 11 System] ? ????????????????????????????? ? ? [Using Windows Security] [Advanced Configuration] ? ? ? ???????????????????????????? ? [Group Policy Editor] [Registry Editor] ? (Pro/Enterprise) (Home) ? ? ??????????> [Enable Microsoft Defender Antivirus] ? ? [Restart & Verify Functionality] Additional Considerations Third-Party Antivirus Software: If you have installed another antivirus program, it might automatically disable Microsoft Defender to avoid conflicts. To enable Defender, you’ll need to remove the third-party software first. Stay Up to Date: Once enabled, Microsoft Defender will download regular updates for virus definitions and security improvements, ensuring your system remains protected. Verification: You can verify Defender is active by running a manual scan in the Virus & threat protection section of Windows Security or using the Windows Security Dashboard. By following these steps, you should be able to re-enable antivirus protection on your Windows 11 system, keeping your device safeguarded against potential threats