If you are using a third-party antivirus like McAfee or Norton, you will need to look for a similar "Quarantine," "Restore," or "Exceptions" section within its control panel.
Some tutorials suggest placing it in C:\Windows\System32 , but for Steam games, it is more effective to keep it in the game's specific directory. Advanced Troubleshooting If the DLL is present but the game still won't launch: steam apidll resident evil 4 hd work