Windows 11 may overwrite your working legacy Canon driver. Go to gpedit.msc → Computer Configuration → Administrative Templates → Windows Components → Windows Update → “Do not include drivers with Windows Updates” → Enabled.
If MP Navigator EX continues to struggle with your specific hardware on Windows 11, Canon and third-party developers offer several alternatives: canon mp navigator ex 4.0 download windows 11
If you prefer a more modern interface or cannot get MP Navigator to work, Windows 11 has excellent built-in alternatives: Windows 11 may overwrite your working legacy Canon driver