If the file is completely gone and verification doesn't work, a clean reinstall is the most reliable way to restore all dependencies. the game via Steam or your Windows Control Panel. Restart your PC.

Downloading DLL files from third-party sites can expose your computer to risks. These files could be modified versions that might harm your system or introduce additional errors.

Antivirus software often incorrectly flags steam_api.dll as a threat and "quarantines" it. Open your antivirus or Windows Security . Go to Protection History or Quarantine .

A very common reason for this error is that your antivirus software has mistakenly removed the file. Many antivirus programs can be overzealous and flag modified files for non-legitimate copies, but even official files can sometimes be flagged.