Halo: The Master Chief Collection has been plagued with matchmaking problems since its initial launch, but a fresh update from developer 343 Industries' should be available the next time you boot up the game. As detailed on Halo Waypoint, the 523 MB patch focuses on "a number of matchmaking issues, fixes various bugs related to UI and the party system, and also improves overall stability."
While a bulletpoint breakdown of the update can be found after the break, highlights include tweaks to how the matchmaking system handles pairing, a change so that custom game settings remain applied to followup matches, and efforts to improve stability both for the user interface and for parties trying to find a match.
Previous updates have also addressed matchmaking issues, but The Master Chief Collection has yet to reach a stable state for many players. 343 Industries head Bonnie Ross has vowed to "make this right with our fans" once the The Master Chief Collection's persisting issues have been resolved.