AKA: The Return of Max
The X-Files is simultaneously a continuity heavy and continuity light show. It has its building plotlines yes, but they are fluid and often getting changed or retconned on the fly and there tend to be long gaps between plot movements because of the monster of the week episodes. As such as plot that, in a more plot focused show like Battlestar Galactica might take a season and a half, takes 5 seasons to play out. And as a result, I think it's awfully presumptuous for The X-Files to expect it's audience to remember a character who appeared in one episode, nearly 4 years ago.