In a story about the filming of the final episode, the New York Times' Bill Carter wrote that most of the series' biggest characters were onstage to film the reunion, "minus the biggest one, Steve Carell’s Michael Scott."
And Cast member Craig Robinson recently told IGN Monday that a Michael Scott cameo wasn't in the cards.
I wish, I wish that that was the case. You know it was a big question: "Was he coming back?" And it was like, he said his good-bye, so they didn't want to overshadow the whole finale with that, because Michael had already said his good-bye.
According to Screen Crush's Kevin Fitzpatrick, who's still holding out hope for Scott's reappearance, returning cast members will include Mindy Kaling, B.J. Novak, Rachael Harris, Dakota Johnson, Joan Cusack and Ed Begley Jr.