To fix the steam_api64.dll (or steam_api64r.dll) missing error in Call of Duty: Black Ops 3
Ensure your Steam client is up to date:
, the most effective verified solution is to verify the integrity of your game files through Steam. This process scans your installation and automatically redownloads any missing or corrupted files, including DLLs. Verified Fixes for Black Ops 3 Verify Integrity of Game Files: Open your Steam Library. To fix the steam_api64
Important: Do not rename any files. The exact filename must be steam_api64.dll. To fix the steam_api64