Here's a problem I have all the time.  I even think I have posted about it before.
 
1. I have a Kontakt instrument in a track.  (In this case, a Scarbee Jay Bass.)
2. The volume slide in Kontakt is turned way down low.
3.  There are not Controller events (or any other kind of events in the track).
4.  I can move the slide up louder, but as soon as the track starts, it will jump back down to a low setting.
 
What the heck?!?

If there is no volume event or CC7 or 11 perhaps inserting one will help. I assume you are talking about the Kontakt mixer volume. There is also a volume control in the control panel toward the right next to the pitch control.  

I tried inserting a Controller 7=127 and a Controller 11=127.  This did not work.  Thanks for the idea, though.

I didn't it would but it couldn't hurt to try. I do think it could be automation is causing it to move back.

The problem exists in the Scarbee Bass Instrument. The same thing happens to me. If I raise the instrument fader (in Kontakt) higher than -6, it will snap back to -6 as soon as I press play. The Sonar MIDI fader is set to full(127). 
 
Some of my Scarbee instruments will not let the fader go higher than -6 via Sonar's MIDI fader. The Mark I Electric Piano, PreBass Amped both won't. 
 
I swapped in "The Giant", "Scarbee Rickenbacker", "Scarbee MM Bass Amped" and their Kontakt volume goes up to "0" - when Sonar's MIDI fader is set to full (127). 
 
Meanwhile, I swapped in "Berlin Concert Grand" and it's Kontakt volume goes to +12 when Sonar's MIDI fader is at full (127)
 
 
 
 

Aaaaaaaaaaaaaaaaaaaand, I just figured it out. 
 
1) Click on the wrench.
 

 
2) click on "Instrument Options."

 
3) Select Midi Controller #7 (Volume) range as desired. 

 
 4. Click "Close."
 

I'll check it out.  Thanks for going to all the trouble to post the screen image!

Nice tip cheers!

Nat -
 
That is a great tip! I've run into this occasionally and never found  the real solution. Thanks very much!

My pleasure.