Failure to meet the objectives such as getting detected when you shouldn't, failing at Eavesdropping, or losing a target will result in becoming Desynchronized. If you go outside of the available memory if you do not return to the allowed space immediately you will automatically be desynchronized.

What happens if you Desynchronize in Valhalla?

Inversely, a loss of synchronization results in the instability of the memory, which eventually culminates in expulsion from it entirely. If such a desynchronization occurs, the simulation will restart from an earlier point.

What happens if you kill too many civilians in Valhalla?

After a two Civilians Kills in Assassin's Creed Valhalla your screen will start tearing and after the third kill you will be Desynchronized. ... Assassin's Creed Valhalla is an action role-playing video game developed by Ubisoft.