Fix OneDrive Sync Stuck on Processing Changes After Migration - Fix Cloudflare Error 521 on Apache Server-Resolving 'Access Denied' in Windows Security

Updated 2026-06-14 00:04:11office-tools
Fix OneDrive Sync Stuck on Processing Changes After Migration - Fix Cloudflare Error 521 on Apache Server-Resolving 'Access Denied' in Windows Security
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.