Could Not Install Canon Mf Port Monitor
This error typically occurs when installing Canon UFRII or PCL printer drivers on Windows (especially Windows 10 or 11). It usually means the printer driver is trying to use a specific USB port monitor that is either already installed incorrectly, blocked by security software, or corrupted.
The Canon installer requires SYSTEM-level access to write the port monitor DLLs to C:\Windows\System32\spool\drivers\x64\3 . Standard user privileges will fail. could not install canon mf port monitor
- Check Event Viewer (Windows Logs → System/Application) for driver signing or policy blocks.
- If on a managed domain, consult IT—Group Policy may restrict installation.
- Temporarily enable test signing only if you understand the security implications (bcdedit /set testsigning on), and revert after.