defender offline scan is not starting

Max de Freitas 20 Reputation points
2025-12-14T20:02:21.94+00:00

Microsoft Defender Offline is not starting on Windows 11 Personal. No error message. I need steps diagnose and fix the problem.

Microsoft Security | Microsoft Defender | Other

Answer accepted by question author

AI answer

2025-12-14T20:02:40.58+00:00

If Microsoft Defender Offline is not starting on your Windows 11 Personal device without any error message, you can follow these steps to diagnose and fix the problem:

  1. Check Windows Recovery Environment (WinRE) Status: Ensure that WinRE is enabled, as Microsoft Defender Offline requires it to run. You can check the status by executing the command:
       reagentc /info
    
    If the status is "Disabled," enable it with:
       reagentc /enable
    
  2. Verify Microsoft Defender Antivirus Settings: Make sure that Microsoft Defender Antivirus is set as your primary antivirus software and not in passive mode. If you have third-party antivirus software installed, consider uninstalling it.
  3. Update Microsoft Defender Antivirus: Ensure that you have the latest updates for Microsoft Defender Antivirus. You can update it through the usual method you deploy updates to endpoints.
  4. Run a Manual Scan: You can manually initiate an offline scan by going to Start > Settings > Update & Security > Windows Security > Virus & threat protection > Scan options and selecting Microsoft Defender Offline scan.
  5. Check Event Viewer: Look for logs in the Event Viewer to see if there are any entries related to Microsoft Defender Offline. Navigate to Applications and Services Logs > Microsoft > Windows > Windows Defender > Operational and check for relevant events.
  6. Restart Your Device: Sometimes, a simple restart can resolve issues with the scan not starting.

If you have followed these steps and the issue persists, consider reaching out to Microsoft Support for further assistance.

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