Fix Windows Search: Connection Refused, Service Not Running - Troubleshoot Windows Defender Sync High Memory-Fix Defender Service Fails to Start on Windows 10/11

Updated 2026-06-14 20:50:44office-tools
Fix Windows Search: Connection Refused, Service Not Running - Troubleshoot Windows Defender Sync High Memory-Fix Defender Service Fails to Start on Windows 10/11
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.