Download and install both the and x64 versions of the "Visual Studio 2015, 2017, 2019, and 2022" redistributables. 5. Run a System File Checker (SFC) Scan
uplay_r1_loader.dll (or uplay_r1_loader64.dll depending on OS system parameters) steam_api.dll
: The main executable file for the Single-Player ( SP ) mode of Assassin's Creed IV: Black Flag. Download and install both the and x64 versions
Assassins Creed 4 Black Flag: AC4BFSP.exe Entry Point Not Found * Download those configuration files for AC4 :- orbit_api & steam_ learn.microsoft.com
Old Uplay data can confuse the uplay_r1_loader.dll file path mapping. Press Win + R , type %localappdata% , and hit . Assassins Creed 4 Black Flag: AC4BFSP
These are associated with Ubisoft’s legacy Uplay platform, now known as Ubisoft Connect. The “r1” designation refers to the first revision of the Uplay API, used by older games like Black Flag to manage services such as digital rights management (DRM), multiplayer features, and—most importantly—achievements.
Technical note for researchers
If you are playing a legitimate version of the game, the best first step is to verify the integrity of your files. This will automatically download any missing or corrupted .dll files.