Today, Ardour crashed repeatedly and gave me a message that said "zombified". I could do nothing at all except to "just quit" without saving and restart Ardour. But then it would happen again after a while.
I'm sorry I have no other information than this, but I do not know what to provide or even what to look for. It was very, very frustrating. I'm just making this post and shutting down my DAW for the day, hoping to come back later to see if someone could at least tell me what to look for in figuring out why this happens.