Fix Windows Security Service Unavailable Permission Denied - Fix Blank Screen After Windows Update in Safe Mode-How to Fix Windows Defender Invalid Configuration Error

Updated 2026-06-13 16:12:54browser-issues
Fix Windows Security Service Unavailable Permission Denied - Fix Blank Screen After Windows Update in Safe Mode-How to Fix Windows Defender Invalid Configuration Error
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.