No information regarding the machine's accuracy is provided, but the fact that you are asked to make a choice implies that it is not perfect. The question explicitly specifies that the prediction has already been made and the contents of box B have already been set. You can't retroactively change the past and make the money appear or disappear by making a decision, so if your choice must match the prediction, then it's not your choice at all. You lack free will, and the decision has already been made for you by the machine. In that case the entire question is meaningless.