John
Its funny I never got out of the habit of stopping the transport before I do anything to a project. I do this with every DAW I have ever used. I would exempt automation. I have and do write automation while the project is playing back.
 
If I insert any plugin I always stop. Doing any routing I stop. Adding a track or bus I stop.  
 
I also use freeze when I am done with editing a MIDI track and or a synth. 
 
I have been known to mute tracks I no longer want in the mix.
 
 

The problem isn't really about turning things on and off during playback though. That was really just a side discussion about Sonar's engine. The problem is with looping. 

I've had also some out of sync issues with MIDI and synths in Sonar. But only if I was looping a section and changed the length of that section during play. When I stopped and restarted then there was no issue in my case.
I don't know if it helps you Sharke, but I can tell you that I always use the audio of synths for mixing. But in my workflow I have first a "synth" project for the song, then export the synths to audio files and mix in a NEW project. Like that I have almost no problems with Sonar, also with my computer's performance.

I’ve had similar issues with looping. So far, it’s ALWAYS been a plug-in issue especially Izotope plug-in’s. To verify I simply toggle the “FX” button off. That has always immediately allowed looping to “work.” I then know I have a plug-in issue and I manually turn them off a class at a time to discover the culprit. Now that I think about it, Izotope plug’s have always been the guilty party.

This has been my experience.

marled
I've had also some out of sync issues with MIDI and synths in Sonar. But only if I was looping a section and changed the length of that section during play. When I stopped and restarted then there was no issue in my case.
I don't know if it helps you Sharke, but I can tell you that I always use the audio of synths for mixing. But in my workflow I have first a "synth" project for the song, then export the synths to audio files and mix in a NEW project. Like that I have almost no problems with Sonar, also with my computer's performance.

Yeah I could do that, but of course it makes things difficult if you decide you need to tweak the synth later. 

sharke

marled
I've had also some out of sync issues with MIDI and synths in Sonar. But only if I was looping a section and changed the length of that section during play. When I stopped and restarted then there was no issue in my case.
I don't know if it helps you Sharke, but I can tell you that I always use the audio of synths for mixing. But in my workflow I have first a "synth" project for the song, then export the synths to audio files and mix in a NEW project. Like that I have almost no problems with Sonar, also with my computer's performance.

Yeah I could do that, but of course it makes things difficult if you decide you need to tweak the synth later. 

I agree that there is little extra effort. But to reduce that, I export the audio files of the synths to my song audio folder and then reference them only in the 2nd project (no copy to Sonar project) and if I have to change the synth afterwards I just repeat the export and voila, the audio file is automatically the new one when I open the mixing project!

msmcleod
The way I work around it is to always start projects on bar 3, using bar 1 & 2 for my count-in. I know I can set the metronome to count in 2 bars, but this way it any potential stuttering is gone before the actual music starts.

That’s not a bad policy in any DAW. It gives MIDI clock a bit of time to settle down and run steadily as well as things like PDC.

I generally start around bar 9, that way I get plenty of time to send CC messages to synths as well.

MagickT
I think that I have similar problems when connecting ableton to sonar via rewire. I create a simple loop in ableton drum rack such as 4x4 kick. And sonar chokes every time when I press play button at the loops start. When I try record it to audio in sonar (create audio track and route sound from instrument track with ableton to this audio track) I have similar thing: first kick of recorded loop is corrupt as if 2 DAW do not work synchronously and ableton starting first and sonar recording audio not from beginning.

The two DAWs have to sort out MIDI clock and other timing information before they will run in time with each other. Which takes a little time to happen. Trying to record from beat one of bar one is always a gamble, it might work or it might not. MIDI controlled synths have the same issue - it takes a little time for everything to get in sync.