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Fix Windows Defender Connection Refused via Registry - Windows Security for Ubuntu Installation Checklist-How to Fix Windows Defender Error 504 in 5 Steps

2026-06-13 14:54:08office-tools
Fix Windows Defender Connection Refused via Registry - Windows Security for Ubuntu Installation Checklist-How to Fix Windows Defender Error 504 in 5 Steps

Final checklist

  • Confirm that the same symptom is gone after a restart or refresh.
  • Keep the smallest working change and undo temporary diagnostic settings.