Get Smart had lost episodes of a different sort: a dispute over copyright ownership of much of the final season of the series (after it was cancelled by NBC and picked up by CBS) was resolved by restricting the syndication licensing of most of the season, limiting them to no more than three airings per station, and imposing reporting requirements on those airings. With most stations either using up their allotment of airings early, or simply refusing to air the affected episodes, they went unseen for many years. In addition, the black-and-white pilot, which was of odd length, and differed significantly from the format of the actual series, was almost never aired.
Read more about this topic: Lost Episode, Affected Series