Changing a model instance might need two references of the same ecore-model. I had the problem, that trying to execute a transformation that was a few days old again, caused the problem, that it just produced an empty output file.

It helped to add the same ecore-model (maybe copy it again in a new location) as a metamodel mappings entry in the qvto-project's properties. Afterwards adding a new modeltype as follows:

modeltype FSM uses "mdsebook.fsm";

modeltype FSM_Out uses "http://www.itu.dk/people/wasowski/dk.itu.smdp.fsm";

After one successful execution, it was also possible to change it to

modeltype FSM uses "mdsebook.fsm";

modeltype FSM_Out uses "mdsebook.fsm";

but also to remove the second modeltype completely:

modeltype FSM uses "mdsebook.fsm";