Fix Windows Defender Security Center Module Missing Error - Troubleshoot 'Connection Refused' When Using localhost in Command Prompt-OneDrive Sync Service Error After Update

Updated 2026-06-14 04:05:27browser-issues

Fix Windows Defender Security Center Module Missing Error - Troubleshoot 'Connection Refused' When Using localhost in Command Prompt-OneDrive Sync Service Error After Update

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.