ARGH!!! This is probably the most simplest thing I've overlooked, but this has had me stumped for nearly 2 hours now. I've exported so many times, I'm not sure what I'm doing differently. 
 
The problem I'm having, I solo a particular track I want to export, select export from the File menu, confirm bit depth etc. and click export. The bar in the top window just keeps looping round and round though. It'll go up to 100%, then start again, up to 100% and start again, so on and so on.
 
Please help 

My usual recipe for weirdness is save the file, close the program, re-open the program, then re-open the file. 

I'm not sure but I've never used Solo for a single track, I just Select / highlight that track.  I'm not sure if solo will export just that track.
If it's a midi track I would probably bounce it to an audio track first.
 
Another trick is to just open the wave file from the Sonar projects audio folder into a wave editor and then edit and save it in the format you want.

Anderton
My usual recipe for weirdness is save the file, close the program, re-open the program, then re-open the file. 

Cactus Music
I'm not sure but I've never used Solo for a single track, I just Select / highlight that track.  I'm not sure if solo will export just that track.
If it's a midi track I would probably bounce it to an audio track first.
 
Another trick is to just open the wave file from the Sonar projects audio folder into a wave editor and then edit and save it in the format you want.

Thanks guys, was a senior moment! Was solo-ing instead of just selecting the track I wanted, I assume it was then exporting each and every track, hence the looping round. All sorted now. Thanks again