I received the following error message when exporting audio: "An internal error occurred while processing the mixdown. The operation was unsuccessful."  I've used Sonar for years, and I have never encountered this error message.  Likewise, I can't find a fix for the problem either.   I'm stuck.  Can someone help?
 
 

Welcome to the forum!
 
I had an issue with disc write permissions when attempting to export audio to a flash drive that caused this error (which may or may not be anything to do with your problem as it seems to be a fairly broad description). Have you tried running Sonar as administrator and/or writing to a different HDD?

Thanks for your answer.  I tried to write to a different HD, but got the same result.  The funny thing is that I had already exported this file a couple of times already, but I didn't like the result, to I made some minor changes and that's when the problems surfaced.  I'm going to try exporting by not selecting different individual tracks to see if that's the problem.  

Try "select none"  before exporting. I've always used this as I found "select all" iffy. 
Did you add any weird plug ins on this attempt 

I'll try your suggestion.  No unusual plug ins added.  However, I discovered that the problem is being created by one track. I'm going to copy and paste it into another track without any effects and see if I can mix down everything. Its very odd, I've used Sonar for a long, long time and this type of problem has never surfaced. Oh well, live and learn.  Thanks

Problem has been solved.  I used Melodyne to correct the pitch on a vocal tract.  Melodyne requested that I increase the size of the cache.  I did.  However, once I brought the range of the cache down to prior levels, the problem went away.  

Great work! Melodyne is a great tool but can be a little flakey. I find it best to clone the track to be adjusted before adding melodyne then render the changes as soon as possible.

Good suggestion, I'll try it.  Melodyne is a good tool for limited circumstances, in other words I try to get the takes in tune rather than relying on Melodyne.   It takes a lot of memory and it taxes computer resources. I will note that I should have said buffer instead of cache in my response yesterday. Oh well, it was a long day.

kdjensen
Melodyne is a good tool for limited circumstances, in other words I try to get the takes in tune rather than relying on Melodyne.  

Lol....without Melodyne, I'm a mediocre singer.....with Melodyne, I'm just a bad singer.

I have had this issue and it has always come down to having to bounce some clips before the export.  I would bet that if you had bounced the melodyne clips down first it might have worked. I have seen the error without Melodyne clips but there must be something with some clip data that it doesn't like that bouncing them down fixes?
 
Just my experience