Yes, you can leave your bread in the bread maker over the night while it is baking. But it is important that you are aware when the bread is done baking so you can get it out immediately. Because if not done, the bread will get tougher and browner than you would have wanted. This is because even though the machine has stopped baking and is off, the steam that is still trapped in the machine will continue to act on the bread, still baking it. So, for this reason, it is best to get the bread out of the pan once it is ready. Another reason is that it might get difficult to divorce the bread from the pan or the kneading paddle if it is stuck and cool before you try to detach.