Uninstall the game completely → delete leftover folders ( Documents\My Games\Far Cry 4 ) → restart PC → reinstall from Ubisoft Connect or Steam.
Quick checklist (summary)
Drop the exact error code and your launcher (Steam, Epic, or Ubi Connect) in the comments below (or consult the Ubisoft support forums with your detailed logs). how to fix far cry 4 uplay-r1-loader64.dll missing
Method 1: Restore the File from Antivirus Quarantine (Recommended) Uninstall the game completely → delete leftover folders