The safest and most efficient way to replace a missing steam_api.dll file is to let Steam do it for you. Steam will scan your game directory, identify the missing file, and download an official, clean copy automatically. Launch the client. Navigate to your Library . Right-click on Resident Evil 6 and select Properties .
Because steamapi.dll is an executable code file, it is a prime target for malware authors.
A sudden crash, power outage, or network interruption during download can corrupt game files.