Unfortunately the main menu freeze/crash still is an issue and I have not seen any solid solutions. This is a multifaceted issue for several people across all console models that has persisted for at least half a year now. Once again I will break down the problems I experience but this takes different form for different people:
CONSOLE: Xbox One S
GAME: Any/all (main menu of MCC). Digital version of MCC.
ISSUE: When starting Halo MCC, if any other game has been opened/played prior to starting MCC, MCC will stutter and freeze directly before or during the loading circle on the main menu after pressing start. It seems to usually happen when custom user settings are being loaded (I set my brightness to 5 and the menu starts a bit darker, so I will see my brightness adjust immediately as the game freezes). When the game freezes it always crashes to the Xbox dashboard. The game will freeze in exactly the same manner if it is opened after a crash. The only solution I have found is to restart the console, and then after a restart, MCC will work fine as long as it is the first game opened. If any other game is opened first, or after closing MCC, MCC will freeze at the main menu after pressing start upon loading it again.
REPRO: Only a certain amount of people have experienced this particular crash but it occurs across all console models. For those who deal with it, it is as simple as starting the game and pressing start to get the crash.
Additional info: This only started happening after a certain update but unfortunately I do not remember which one; it is at least a half year old. This may or may not be tied to other crashes I and others have also experienced, such as crashing during Halo CE loading screens (some of which turn the Xbox off on their own). There has been some talk of the Xbox Insider program being part of the problem but I am not 100% sure. Steps I've taken to solve this issue include uninstalling/reinstalling the game, deleting and reinstalling my save data, hard reset(s), clearing Blu-Ray disc persistent storage. At times this issue will disappear and come back at random with no explanation.
I personally have not seen any official announcement on this bug for months and months, I sincerely hope the team is aware of it because those of us experiencing it do not want to restart our console every time we want to switch games. It can make playing MCC a frustrating and tedious experience.