I'm getting an error message when I try to mix down my project in Sonar 8.5. It says that an internal error occurred. Same happens if I try do an mp3. I used to be able to do this, can't see what I'm  doing wrong.

michael diemer
can't see what I'm  doing wrong.

1. Probably a corrupted project.
2. Rogue VST/VSti
 
Either was I would start by opening the project in safe mode eliminating all VSTs one at a time but keeping VSYi's if you have MIDI/Softsyths. See if you can export then.
 
If not start by opening the project in safe mode eliminating all VST/VSTis, See if you can export then.
 
If not it's probably a corrupted project.

Thanks Bapu. This project did get corrupted at one point, and I rescued it with safe mode.
Before trying your suggestions, I'm wondering if recording it the old fashioned way might work? I used to do this in HS6. Record the midi as an audio track, and then make a wave from that. I'll see if that works.

Hope you get it sorted out.

Well, the old-fashioned method didn't work. It recorded to an audio track, but there's no sound. So I tried the Bounce method. I made an audio track of the entire mix. It plays fine. But then when I go to Export as wav or mp3, I get the error message again (internal error). So at this point I have an audio file of my project, is there some other way to make a wav/mp3? Perhaps using something other than Sonar?

You could try: delete aud.ini and let SONAR rebuild it.
 
Or re-install 8.5.

Solved, but not sure how. I found a wave file in Audio which I must have made today, possibly it's the audio track created when I did the bounce. From that I successfully made an mp3.

Yes, if you've successfully bounced to track within the same project, you can either use that file directly from Windows Explorer, or simply drag it from your project onto your desktop.
 
This doesn't explain though why you cannot export directly.
 
Depending on the complexity of the project, a rebuild might be the only solution.
 
If you decide to do this, do it in a specific order - start with duplicating your tempo map, then meter/key changes, then your bus structure.
 
Do all of this before looking at synths/midi/audio tracks. Then finally do your plug ins.

Thanks, Jonesey. That seems like an awful lot of work, so as long as I can do it the other way I might as well. Once I have a suitable wave/mp3, I'm basically done with the project. Which I do. Hopefully my future projects will not become corrupted.

As a short cut, you could try doing a "save as" to a different folder location. Make sure you've got "Copy audio With 
Project" checked.
 
This will only copy the actual audio referenced by the project.