Fix 'Port Already Allocated' Error in Windows Defender on Windows 10 - Microsoft Store Stuck in Login Loop-Troubleshooting BitLocker Error 504 on Drive Unlock

Updated 2026-06-14 16:05:26cloud-software
Fix 'Port Already Allocated' Error in Windows Defender on Windows 10 - Microsoft Store Stuck in Login Loop-Troubleshooting BitLocker Error 504 on Drive Unlock
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.