There are five common reasons for this error:
If the file is already on your system and you want to check its safety: Steam-api64r.dll File Download
Errors like "steam_api64.dll is missing" or "not found" typically happen for three reasons: There are five common reasons for this error:
The file may have been accidentally deleted during a manual game update or cleanup. Steam-api64r.dll File Download
Check your antivirus quarantine folder to see if steam-api64r.dll was blocked.
: Your security program may have moved the file to quarantine thinking it was a threat Corrupt Installation