Report Clone left running in background in LabVIEW General Posted Thursday at 04:39 PM I do something close to Neil. My messaging structure uses the user events, and so in my event structure I have a long timeout of say 5000ms. In that timeout case I check to see if the user event is valid (not a number/reference). If it isn't valid then go clean up, I probably forgot to send a quit message or something shutdown improperly. I made an idea on the idea exchange to generate an event, when a reference gets destroyed over here which would make this a bit more graceful.