A non-functioning Windows Defender may let viruses, malware, and other security concerns compromise your machine. Older software, issues with outside security applications, or system file corruption can all cause this problem. Maintaining system security depends on Windows Defender operating as it should be. This guide offers precise, methodical fixes for Windows Defender problems.
Common Causes of Windows Defender Not Working
- Conflicts with Third-Party Antivirus Software – Some security programs disable Windows Defender.
- Outdated Windows Defender Definitions – Missing updates can cause functionality issues.
- Corrupt System Files – Damaged OS files may prevent Windows Defender from running.
- Disabled Windows Defender Service – The service may be stopped or misconfigured.
- Group Policy Restrictions – Some policies may block Windows Defender from functioning.
How to Fix Windows Defender Not Working
Restart Your Computer
A reboot can resolve temporary issues preventing Windows Defender from starting.
Check for Third-Party Antivirus Conflicts
If you have another antivirus installed, disable or uninstall it.
Go to Control Panel → Programs & Features and remove conflicting security software.
Update Windows Defender
Open Settings -> Update & Security -> Windows Security.
Click Virus & threat protection and update protection definitions.
Restart the Windows Defender Service
Press Win R, type services.msc, and press Enter.
Locate Windows Defender Antivirus Service, right-click it, and select Restart.
Run the Windows Security Troubleshooter
Open Settings -> Update & Security -> Troubleshoot.
Select Windows Security and run the troubleshooter.
Scan and Repair System Files
Open Command Prompt as Administrator.
Run the following command:
sfc /scannow
If the issue persists, run:
DISM /Online /Cleanup-Image /RestoreHealth
Enable Windows Defender via Group Policy (For Enterprise Users)
Press Win R, type gpedit.msc, and hit Enter.
Navigate to:
Computer ConfigurationAdministrative TemplatesWindows ComponentsMicrosoft Defender Antivirus
Perform a System Restore
Open Control Panel -> Recovery -> Open System Restore.
Choose a restore point before Windows Defender stopped working.
Reinstall Windows Defender
Open PowerShell as Administrator.
Run the following command:
Get-AppxPackage Microsoft.SecHealthUI -AllUsers | Reset-AppxPackage
Seek Professional IT Support
If Windows Defender remains unresponsive, expert help may be required.
TechNow provides expert IT support services in Germany to resolve Windows security issues efficiently.
Fixing Windows Defender issues ensures your system remains protected against cyber threats. If you need professional assistance, TechNow offers dedicated solutions for restoring Windows security features seamlessly.
Restart your computer and check if Windows Defender is functioning.
Ensure that Turn off Microsoft Defender Antivirus is Not Configured or Disabled.
