Fix Windows Security Proxy Error After Update - Resolving OneDrive 0x8004de40 by Resetting Sync-Windows Security Cache Full: Causes and Solutions

Updated 2026-06-14 16:22:53windows-fixes
Fix Windows Security Proxy Error After Update - Resolving OneDrive 0x8004de40 by Resetting Sync-Windows Security Cache Full: Causes and Solutions
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.