On projects with midi playing back if I hit the stop button, go to different mmeasure, then play, sonar plays the last midi note(s)it was playing previously along with the correct audio/midi at the new measure. It's like it is still in the audio buffer. I have unchecked play audio tails as well as changed fade out under adavnced options to 0. I essentially have to hit stop, then disengage the audio engine, the reengage the audio engine (Which causes the tail in the audio buffer to finish playing and fade out), then hit play to get only the current audio/midi to playback alone correctly. the reset midi button has no effect. How can I correct this? Thanks

Was having similar issues which you described... it seems to happen only when certain Audio Plugins are used on the Instrument Track; in my case its with IK Amplitube. however, i was able to resolve this issue. hope the following helps you too...

1. enable the "Play Audio Tails"
2. when ever you stop the playback, notice the fall in the VU Meters. 
3. wait until the Peak has completely disappeared from the meters. 
4. when you press PLAY again, you should have everything play as it normally should.

Couple of checks you may want to try...
1. leave the first (1 bar) blank
2. always start on the second (2 bar)
3. play the track until half way and stop
4. rewind to the beginning
5. if you play immediately; you will still hear the tails or a pop
6. if you wait like the above; you should start without any sound (like it all should). notice that on the MASTER and MONITOR tracks, during the first bar, the db number is blank. (ie minus infinity; totally no signal) (once the signal comes in the db number will start jumping)