Fix Windows Defender Real-Time Protection After Clean Boot - Explorer.exe Restart Loop: Windows 10 Troubleshooting Guide-Cloudflare 521 Error: Firewall Settings Fix

Updated 2026-07-28 18:29:32developer-tools
Fix Windows Defender Real-Time Protection After Clean Boot - Explorer.exe Restart Loop: Windows 10 Troubleshooting Guide-Cloudflare 521 Error: Firewall Settings 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.