Running Sonar Platinum 2017-07 (but also had this problem on previous versions)
 
When I'm ready to export a song - all tracks going to the master bus.  On almost every export I get a split second of distortion at the beginning of the exported track (44.1 16bit mixdown).  Or some something that sounds like the trail end of a strong reverb applied to the 1st note.
 
After that, the track sounds fine.  The only way I seem to be able to avoid this is to save, close out my Sonar session, then reopen and immediately export (without hitting play at any point).  
 
Anyone else experienced this, or know how to solve it?  After mixing down 15 songs over the weekend, it was a real time waster to have to do it all over again.  

Any midi tracks there Brian ?
Look for a phantom note at 101:00 Its happened to me before.
 
Cant say ive heard of this before, especially with Save/close/reopen and it solves the problem.
you might be able to work around it by killing the audio engine (in the control bar) before you start the export.
But that's only a band aid till we can figure out the real culprit. which im guessing a plug in or something triggering midi data (Example: Drums).

I believe I've had this before, on a few projects, and as Brian said always with a time-based effect. Is it as if the song was playing on repeat and the end note is looping back into the beginning?

chuckebaby
Any midi tracks there Brian ?
Look for a phantom note at 101:00 Its happened to me before.
 
Cant say ive heard of this before, especially with Save/close/reopen and it solves the problem.
you might be able to work around it by killing the audio engine (in the control bar) before you start the export.
But that's only a band aid till we can figure out the real culprit. which im guessing a plug in or something triggering midi data (Example: Drums).

 
There is usually at least one MIDI track on my projects (a drum program such as AD, EZ Drummer, Drum Core are used frequently), I'll check on the phantom note, but many times it seems like a legitimate note (but distortion or an effect is applied to it that shouldn't be there)  

jonboper
 Is it as if the song was playing on repeat and the end is looping back into the beginning?

Yes, or as if the trailing effect at the end of the song is being applied to the 1st note (but also some distortion is also usually added in addition to say "reverb"

Could be an automation node ?
I know personally I do a lot of nonsense automation, like silencing the beginning of my tracks with automation.
 
you don't notice it though in real time when listening to it ?
Hope the bump helps man

Hi. I have seen this on a few occasions some time back. I have usually either stop/started the Audio Engine, or hit play, followed by stop. And all has been well.
It has happened so seldom, that I never tried troubleshooting it.
All the best.
 

Sounds like an Fx tail that hasn't finished sounding but gets rendered when you Export.
 
It’s a good idea to add an extra measure to the end of your project to contain any reverb tails that your effects produce.

IIRC, I have had this happen to me when stopping a project before the end, and then exported.
But as Bristol_Jonesey says, it sounds like an effect hasn't stopped sounding on my end.

Brian Walton

Yes, or as if the trailing effect at the end of the song is being applied to the 1st note (but also some distortion is also usually added in addition to say "reverb"

This is exactly what I've experienced. Seems like a lot of us have heard from time to time.
 

Zargg
 
IIRC, I have had this happen to me when stopping a project before the end, and then exported.
But as Bristol_Jonesey says, it sounds like an effect hasn't stopped sounding on my end.
 

 
I never thought that much about what it was, just took it as an artifact. There was a song where I liked it so much that it inspired an introductory tone:
 
https://booleanoperators.bandcamp.com/track/gumming-for-summing
 
That saxophone tone at the beginning was the result of falling in love with the mess.

chuckebaby
Could be an automation node ?
I know personally I do a lot of nonsense automation, like silencing the beginning of my tracks with automation.
 
you don't notice it though in real time when listening to it ?
Hope the bump helps man

Nope, even happens with projects that are jazz related with no automation (dynamics within the players)
 
Also is not heard in real time playback, thus the frustration when it happens on export
 

Zargg
Hi. I have seen this on a few occasions some time back. I have usually either stop/started the Audio Engine, or hit play, followed by stop. And all has been well.
It has happened so seldom, that I never tried troubleshooting it.
All the best.
 

This was a good thought, but the start/stop audio engine doesn't fix it either and I tried multiple combinations
 

Bristol_Jonesey
Sounds like an Fx tail that hasn't finished sounding but gets rendered when you Export.
 
It’s a good idea to add an extra measure to the end of your project to contain any reverb tails that your effects produce.

Also a good thought, but doesn't seem to solve my issue.  Still happens with extra "blank" time at the end of the track.  Still get a stutter/distorted note/heavy effect processed note at the very beginning of the exported file.
 
 

chuckebaby
Any midi tracks there Brian ?
Look for a phantom note at 101:00 Its happened to me before.
 
 

No phantom note at 101:00 - confirmed on multiple projects. 
 
Just confused...