Select and add the file (or the entire Mafia 3 folder) to your Exclusions or Whitelist to prevent it from being deleted again. 2. Verify Game File Integrity (Steam Users)
The steam_api64.dll file is a critical component used by Steam games like Mafia 3
If the file is actually missing or corrupted, Steam can automatically redownload it for you. Open your . Right-click on Mafia III: Definitive Edition . Select Properties > Installed Files . Click Verify integrity of game files . Wait for Steam to scan and replace any broken components. 3. Reinstall Visual C++ Redistributables
Let’s break down what this file is, why the error happens, and—most importantly—how to fix it properly. We’ll also address the “full” part of your search and why you should be careful.
If you mistakenly deleted steam_api64.dll (the legitimate version) and thought you needed steam_api_ext.dll , follow this recovery process: