If you haven’t started the game yet or are willing to reinstall, do this:
The "Door Bug" is a game-breaking progression error. It typically occurs when the player attempts to interact with a lever or button to open a door or activate a mechanism. The animation plays, the sound triggers, but the door remains shut. This is caused by the game engine failing to synchronize the physics or the script trigger, often related to the game running too fast on modern hardware or corrupted script files in pirated repacks.
: Older cracked versions were never patched by Ubisoft. If the difficulty trick fails, look for a "v1.1 Crack Fix" specifically designed to address the DRM-related door bugs.