Hi, my second post on this. I was hoping it was an isolated incident in one project and it's now hit a second as well.
 
I can't export a project. An error occurs. It's not due to plug-ins, I can take every single plugin out, every vst, you name it. I've tried everything known to man. Been using Sonar since Pro Audio days, probably done 1,000 charts. System is up to date, X3 is up to date, all other software works fine (I'm an arranger and use Sibelius all day long, no problems).  Ive' run every test on my computer. Any advice? I'm at the end of the line here, unless I can figure this out I'll have to switch DAWS after 18+ years, but if I can't export the project as a .wav there is no reason to continue. Thanks in advance. 

Hi. What kind of error do you get? What specifically does the error message say? What does the two projects have in common? Can you export audio from other projects? What have changed with your system lately?
All the best.

Thanks for responding.
Error message: "An internal error occurred while processing the mixdown. The operation was unsuccessful". 
 
I can export other projects.  All projects are extremely similar with just about everything: track count is medium I'd say. I have a quad core with 8 gigs of ram, I was doing similar projects with Sonar 8.5 with a dual core and a measely 3 gigs of ram. I've made no changes to my computer. 

Are you doing fast or real time bounce / export?

Both. When I do slow bounce I still have an error, but it will render about 1/3 of the project and ask me if I want to keep it. 

Temp disable antivirus.
Close as many apps and services as you can (memory issues?)
Try saving it to another hard drive.
Run chkdsk/R from an administrative command prompt.

The same thing happened in the post below in the link, read it and see if the suggestions help.
How much Ram do you have?
 
Sonar mix down Error

Thanks for the responses. I have 8 gigs of Ram. I was doing similar projects on other computers with 1 gig ram, or 3 gigs ram.
 
chkdsk says everything is fine. I've tried everything else as well. 
 
I'm at a loss here. On one project, I can select "most" of the tracks" and it will export, but not all. As I said before, I was doing the same projects with 1 gig in the past (I think that was Sonar 3) and 3 gigs (Sonar 8.5)  Ive only had problems with X3. Computer is up to date, X3 is up to date. Most projects will export, there is no "pattern" whatsoever of why I am having trouble with 2 of them. One of them isn't even very big. Frustrating. 

Have you tried to save as new project, and open that instead? Could be some sort of error in those original projects. Have you tried to open in safe mode?
All the best.

Musikslayer
chkdsk says everything is fine. I've tried everything else as well. 

 
You actually ran chkdsk /R for all your hard drives from an administrative command prompt? 
 
Cheers..