Because the file is modified, you cannot access official Ubisoft online features like Just Dance Unlimited or the World Dance Floor without a valid Ubisoft account and a clean (non-modded) sysNAND, as these require connecting to live servers.
Malicious actors frequently name their files after popular games or exact software updates to trick users. A compressed .rar file can easily hide executable malware, spyware, or ransomware that activates the moment you unpack it on your PC. 2. Adware and Malicious Redirects just dance 2021 nspupdate v327827644899rar work