Desynchronized

This is the process where you have failed to meet the objectives of the game and basically get a game over and return back to the last main point. There are a few ways in which this can happen.

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.

If you lose all your health and die then you will desynchronized.

If this happens you will be forced to return to the last main memory point and start from there. In Assassins Creed it basically means you did something that Ezio, Connor, or Altair didn't do. Apparently in AC1 it was swimming a lot of the time and in AC3 you might accidentally kill George Washington. It's pretty similar to a Time Paradox if you ever played Metal Gear Solid.