Wait for Steam to scan your installation. If it detects that steam_api.dll is missing or altered, it will automatically download a fresh, official copy directly from the Steam servers. Method 2: Check Your Antivirus Quarantine
Add the Resident Evil 6 installation folder to your antivirus or Exceptions list to prevent it from being deleted again. Method 2: Verify Integrity of Game Files on Steam fix free download steam apidll file resident evil 6