This system required players to maintain a constant internet connection to a Ubisoft server. If your connection flickered, or—more infamously—if Ubisoft’s own servers went down (which they did, especially during the 2011 DDoS attacks), you were locked out of your single-player game.
For players who want to experience Assassin's Creed 2 without the need for an internet connection, there are alternative options available:
In this article, we will break down exactly what this phrase means, why "Server 21" matters, how a single-file crack works, and whether you should use it in 2026.
If you are specifically looking to use the old emulator: