This is officially bugging the bejesus out of me. 

I have a synth track containing a Reaktor synth, Junatik. Every time I stop playback in X2, the master volume on this synth is reset to zero. I have to put it back up every time I start playback. There is absolutely no automation whatsoever on the track. 

Does anyone have the slightest idea of what might be causing this? It's definitely Sonar related because I have used the same synth in Pro Tools with no problems. 

I just tried this and it does not happen in my case. I don't know what you might have different. All I can suggest is you look at the channel's MIDI event list or put a MIDI Monitor in the Reaktor ensemble.

Or maybe it is this: the Mod Wheel controls the output Level - you can turn that off in the Level properties:

Aha! That did it, thank you. I guess I'm not that great with the settings in Reaktor!

It was pretty well hidden. You can't tell unless you look inside.

Yeah Reaktor is one of those synths you have to put a lot of effort into understanding. Me so lazy 

Yes, it has a huge learning curve.

Both Reaktor and Kontakt have some hidden gems.

For Reaktor, I kept having the tuning change after playback on a particular patch and it drove me nuts until I figured out it was something I had moved or played that did it unintentionally.

For Kontakt, there are trigger notes usually really really low notes on the keyboard, that cause things to change, like all of a sudden my strings would change to pizzicato (however it is spelled).  Once I figured out that stuff, I edited the patch to change those triggers to notes below anything on my controller and save it under a new name.

I'm quite sure there are more of these kinds of things out there.

Glad this one got figured out, thanks!

Bob Bone