Call of Duty: MW3 Error Prevents Campaign Play Due to Disc Requirement

Some PlayStation 5 players of Call of Duty: Modern Warfare III are experiencing an error that prevents them from playing the game's single-player campaign and asks them to insert the Modern Warfare II disc instead. This issue, along with the absence of a platinum trophy and the listing of achievements as DLC for Modern Warfare II, suggests that Modern Warfare III may have originally been planned as a paid expansion for its predecessor. Activision is aware of the problem and has released an update to address it.