: Some versions of the game crash if the steam_api.dll is outdated or modified. Verifying your game files through Steam is the safest way to repair it. Installation Locations
The steam_api.dll file in is a core dynamic link library used by the Steam client to verify ownership and manage features like achievements and multiplayer. In the context of "exclusive" content, it is often associated with the Resident Evil 6 x Left 4 Dead 2 crossover, which is a permanent, free update exclusive to the PC version. PC-Exclusive Content Overview steamapidll for resident evil 6 exclusive