Hi AngDLD.
If the two-sided printing is occurring, even after two-sided printing has been unchecked in the upper part of the print window, check the print sub-menus, particularly the Layout sub-menu. If this is occurring with even the Layout submenu set to single-sided, then the printer will need to be removed and then reinstalled using Canon's drivers (available free of charge HERE).
Did this answer your question? Please click the Accept as Solution button so that others may find the answer as well.
