I fully installed the Halo reach campaign and multiplayer, but neither are playable for me. Whenever I try get into a multiplayer game it will tell me “The following required content is not installed: Halo reach multiplayer.” The same issue for the campaign. I’ve restarted my xbox a few times and restarted mcc a good number of times but the same problem occurs. I installed the Halo CE multiplayer before installing reach and it works perfectly fine.
Please see the pinned thread regarding Halo Support and how to submit tickets for issues you may be experiencing.