I sometimes get this error when trying to export audio.
 
"An unknown error occurred during processing, possibly caused by an invalid parameter."
 
Luckily it usually works the 2nd time I try, otherwise I'd be asking for a refund.

I see you are using Newburyport. Have you tried rolling back to Manchester? I'm still on that one and have had zero issues with it (so far...).
 
Regards,
Dan
 

No, I haven't. I've had issues with every single version of Sonar so I'm not going to roll the dice on this one, sorry.

Kylotan
"An unknown error occurred during processing, possibly caused by an invalid parameter."

best error message ever - I remember seeing that once myself long time ago
 
I bet whoever coded that is no longer with the company

Which plugins are being used?   Most of what Google returned were older items and many referred to Direct-X plugins. 
 
If you bypass all FX ("E") does the export ever return that error?

RehabRob
best error message ever - I remember seeing that once myself long time ago
I bet whoever coded that is no longer with the company

That would be correct - Ron hooked that up back in the day :)
Its a catch all generic error that happens when something low in the stack encounters a problem and returns a failure code, but by the time the error handler gets it its so far removed from the source that the direct error cause was not known. This is a very common software engineering problem. In a debug build we get a ton more logging that would normally pinpoint these sorts of problems more accurately, but this data is not present in retail builds for efficiency.
 
I realize this is frustrating but if this happens often, you need to submit either a recipe or a project file that this can be reproduced with. These sorts of problems are most often caused either by failures due to plugins or some obscure state management issue. The fact that it works the second time reinforces this. I suspect if you played the project once before the export it would probably work as well.

Noel Borthwick [Cakewalk]
I suspect if you played the project once before the export it would probably work as well.

This also gets rid of the mysterious "General Error" dialog box that crops up from time to time. It seems to happen if you do a huge amount of editing without ever playing the project, but this doesn't happen enough for me to be certain of that.