Hi Christophe, I know your are quiet bussy releasing msm but we found something and we do not know whether it is the intended behaviour or a bug. We implemented a little state machine with a submachine. The submachine has an pseudo exit state. If we use "typedef no_message_queue" in the state machine as well as in the submachine, then the state machines get somehow mixed up and do not act normally once you leave the submachine via the pseudo exit state. In that case msm does not exit the pseudo exit state. We followed almost your example that you provide in the documentation. Is that known to you? Does it make sense to fix that or are there serious reasons why msm behaves like that? Regards, Michael