Anti-cheat integrity violations during gameplay.
Game integrity violations
If you get an error message describing an integrity violation while in the game, your current game session has become untrusted. Multiplayer sessions will not be available in this state until the game has been restarted from desktop.
Check that your game installation is up-to-date.
When using Steam, update to the latest game version by verifying the integrity of the game cache:
When using Uplay, update to the latest game version by verifying the game files:
Below is listed the most common integrity violations and fixes to them: