In a microflow, you can define output type. It would be great to mark output as mandatory.
This would assure that the output of microflow is as expected.
Now I find myself lot of time checking for != empty in the microflow which calls the sub microflow.
If there is an end event in the microflow which returns ‘empty’ or an object that is returned is empty, there should be an exception thrown in the flow which called this microflow.
In this way unexpected situations are better handled by Mendix applications.