Fix Windows 11 Installation Assistant Stuck at 99% - Troubleshoot Windows Security App Launch Failure-Fix ERR_CERT_AUTHORITY_INVALID on Localhost

Updated 2026-07-28 01:41:38backup-recovery
Fix Windows 11 Installation Assistant Stuck at 99% - Troubleshoot Windows Security App Launch Failure-Fix ERR_CERT_AUTHORITY_INVALID on Localhost
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.