Missing Episode: 10 episodes. 2 from season 5, and 8 from season 6 to be more precise. You may have seen them in syndication, however.
Screwed by the Network: Though never a top 30 hit, it won its timeslot, many times, and was brought back for a 4th season in 1987, due to fan protests. But ABC would soon begin tinkering with their Friday night schedule, by making sure it was dominated by Miller-Boyett programs. It began in 1987 with Full House as the lead-in for the show. Then a year later, in 1988, ABC moved Perfect Strangers moved to Friday nights. Finally, a year later, ABC moved Mr. Belvedere to Saturday nights, to make way for Family Matters. Only Just The Ten Of Us remained. By the end of the 1989-1990 television season, Mr. Belvedere and Just The Ten of Us were cancelled, and there were no more non-Miller-Boyett shows in Friday nights for the time being.