The 49th was posted to Canada in 1802. As Lieutenant-Colonel, Sheaffe commanded the garrison at Fort George, where he faced an attempted mutiny. Despite his own notable achievements, Sheaffe was often compared unfavourably with the popular and charismatic Brock. Sheaffe had been Brock's second in command prior to their time in Canada, and continued in that role upon their arrival. Shortly after arriving at their new station, a mutiny was attempted by some of Sheaffe's men. Brock hurriedly came to the aid of his subordinate, ended the mutiny without conflict, and arrested the perpetrators. They claimed they took their actions directly as a result of Sheaffe's belligerence, but were subsequently executed after a court-martial. Brock warned Sheaffe to stop working the men too hard and to stop punishing men harshly for small infractions.