Dirac and Audirvana seem to interact strangely in fact.
I had the same problem. My solutions consisted to run a third software (Reaper DAW) to do the measurements/test sounds and to configure the Dirac plug-in. Once this is saved within the Dirac plug-in, I could run it smoothly within Audirvana.
Just to add another problem with Dirac Plug-in here:
The plug-in worked like a charme for weeks and since yesterday, the plug-in doesn’t launch anymore automatically when playing a song. Actually, the song doesn’t start at all, which I found out is related to the Dirac plug-in not starting automatically anymore (out of a sudden). Now I have to launch the plug-in within Audirvana (configuration button) and save it again each time, then it works until the next song/album/playlist.
I don’t know where the problems are, but I wish that the integration of Audirvana and Dirac would work better, as I think that the possibility to integrate such plug-ins is a real plus for Audirvana and Dirac Live Studio is such a benefit add-on to it.
Looking forward to the evolution of this integration.