In most modern cases, Windows Security or third-party antivirus software flags the uplay_r1_loader.dll as a threat and blocks it. Check Quarantine
The uplay_r1_loader64.dll file is a core component of Ubisoft’s legacy Uplay integration. In newer versions of Windows (10 and 11), or after the rebranding of Uplay to , the handshaking process between the game executable and the launcher often breaks. Common causes include: uplayr1dll splinter cell blacklist 2021