Are you "joining" a multiplayer game, or are you hosting one yourself?
Which, if any, DLCs do you use in singleplayer, in multiplayer (if you aren't hosting yourself, what DLCs does the host have?)
In singleplayer - are you attempting to play Ironman? (if you do, do you save locally or on the cloud?)
Which, if any, DLCs do you use in singleplayer, in multiplayer (if you aren't hosting yourself, what DLCs does the host have?)
In singleplayer - are you attempting to play Ironman? (if you do, do you save locally or on the cloud?)