Fix OneDrive Sync Error 0x8004de40 – Authentication Failure - How to Fix Scheduled Task Access Denied-Fixing Windows Defender HTTPS Certificate Errors

Updated 2026-06-14 15:40:21office-tools
Fix OneDrive Sync Error 0x8004de40 – Authentication Failure - How to Fix Scheduled Task Access Denied-Fixing Windows Defender HTTPS Certificate Errors
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.