How to Reinstall Windows Security App (Microsoft Defender) - Windows 11 Bluetooth Icon Not in System Tray-Nginx Config Test Failed: Invalid Parameter Fix

Updated 2026-07-28 09:18:09browser-issues
How to Reinstall Windows Security App (Microsoft Defender) - Windows 11 Bluetooth Icon Not in System Tray-Nginx Config Test Failed: Invalid Parameter Fix
Before changing system settings, save your work and note the exact error text so you can compare results after each step.

Extra verification checklist

  • Restart the affected app after changing permissions or configuration files.
  • Test the same workflow in a clean browser profile or a temporary user account.
  • Compare the result on another network if the error may be connection related.