Changing your beta status can force a client refresh that resolves initialization bugs.
: Right-click the Steam shortcut on your desktop and select "Run as administrator." Then, launch Just Cause 4 from your library. just cause 4 unable to initialize steam api
“Disable Steam overlay for Just Cause 4, then launch the game from the .exe in the binaries folder, NOT the desktop shortcut. Then alt-tab and re-enable overlay while the intro video is playing. Works every time.” Changing your beta status can force a client