This is the single most common cause. Antivirus programs (especially Avast, AVG, and Windows Defender) frequently flag uplay_r1_loader64.dll as a “generic trojan” or “potentially unwanted program” because of how it interacts with game processes.
If the above steps don't work, use your launcher's repair tool: : Right-click the game > Properties Installed Files Verify integrity of game files Ubisoft Connect : Select the game > Properties Local Files Verify files Uplay r1 loader64 dll missing or not found Fix This is the single most common cause