Me and a friend, on MCC for PC (Windows 10) are doing solo Legendary/LASO playlists on both Halo Reach and Halo:CE respectively. Both of us are having this issue. This occurs randomly but more frequently on my end when save/quitting from a mission, and resuming it again from the playlist.
Sometimes the game will not load the most recent save file in the Steam userdata folder, and will instead create a new one which will restart the mission. This is particularly frustrating when trying to progress through tough grenade jumps and such in LASO campaign, or almost making par times and then having to restart the mission.
This happened so frequently that I have amassed 24 different deepSave files over the last three days. I’m pretty sure they are becoming corrupted for some reason and the game cannot load them, so it reverts to restarting the mission, which creates a new deepSave file.
I tried deleting all of the deepSaves and restarted successfully from the first mission. Loaded from checkpoints successfully three times on the second mission.
Up to this point there was only one deepSave file in the userdata folder. This seems nominal.
Then it happened. 4th time I save/quit and resumed it restarted the mission, and it generated a second deepSave file.
Something is happening to these saves and the game refuses to load them properly.
I can provide the aforementioned files that I have backed up if it would be useful in troubleshooting this.