A while back I read on this forum how to make so exporting to audio could be done without many minutes of silence left on there. But it's not working, and my four minute piece exports to ten minutes, the last six of which are silence. Here is what I learned to do from the forum:
 
1. Move to just after the end of my piece
2. Select All
3. Select From = Now, which selects everything after the current Now position
4. Delete
5. File - Export - Audio... Select "What You Hear".
6. Open resulting wav in Audition. Six minutes of silence after actual song.
 
What am I doing wrong?
 

After deletion, is the selection on the timeline still extended past the now marker? Personally I never do the delete step, I do select all to select all tracks/clips and then select a range along the timeline ruler. 

Hi. I have not encountered this issue, but I usually click and drag on the timeline to select the region I want to export (if in my case if I need to export anything other than the whole song). Others may know better.
All the best.

You didn't select a "Thru"

jkoseattle
What am I doing wrong?

I use Select By Time.  I hit Control-A while clickng a track in the track view (which selects all the tracks not muted), then pick a time range with Select By Time (under the Edit menu).  Let's say starting on measure 3 beat 1, and ending on measure 123 beat 1.  That specifically selects exactly the range.  Then I click Export.  I get just that as a result on the exported file - no extra time or silence.

Thanks everyone, you're all saying the same thing in different ways, and that is to select specifically what I want to export rather than leaving it up to what Sonar thinks by not selecting anything. Good plan, that's what I should be doing from now on. Forum to the rescue yet again!!

jkoseattle
Thanks everyone, you're all saying the same thing in different ways, and that is to select specifically what I want to export rather than leaving it up to what Sonar thinks.

 
They say "everyone's a critic," but SONAR isn't. If you slid a piece of audio way over and created an automation node six minutes after your song ended, SONAR will assume you're some kind of avant-garde musician, and you put the automation node there for some reason, and therefore it's part of your song. 
 
SONAR takes everything you tell it literally. Maybe it should start to include a "Dude, is that really what you want me to do?" dialog box when you do something like make a typo and enter 1200 BPM for the tempo