Windows Security Not Scanning for Viruses: How to Fix - Windows Defender Authentication Failed Error Troubleshooting-Windows Security Slow After Update

Updated 2026-06-13 18:09:14macos-help
Windows Security Not Scanning for Viruses: How to Fix - Windows Defender Authentication Failed Error Troubleshooting-Windows Security Slow After Update
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.