Since upgrading to Platinum, the transport no longer stops at the end of the song.  At first I thought it was just the song I had originally recorded in a previous version.  However, I just started a new project and recorded one simple midi track about 1:07 long and the transport just keeps going.  It used to stop when it got to the end of the midi track or the end of the last track (albiet, midi or audio).  I didn't use the mod wheel or sustain pedal that would cause more info to be recorded.  
 
Though I will say that in the other song I had mentioned, there is a piano vst loaded, and when I hit stop on the transport I can hear the sustain pedal is being depressed.  In this song I only have one vst loaded (Omnisphere).
 
Any help would be appreciated.  

Check in the Track view the following.

Options > Stop at Project end (Needs to be checked for the project to stop at the last piece of data in the project)

Ah ha!  Thanks!  I was looking in the preferences...and obviously I couldn't find it.
 
Thanks!!

bsheen
Ah ha!  Thanks!  I was looking in the preferences...and obviously I couldn't find it.
 
Thanks!!

That has nothing to do with my issue however.  My situation is that for whatever reason (and this happens when I have songs/projects in Sonar with absolutely no effects, so it's not an effect, and when I have a VST for like a keyboard or some sound, then after a while the transport just stops functioning.  The stop button becomes greyed out and the song timeline just moves along.  Often the audio stops functioning at this point.  I can save the song, and reopen Sonar and all is well.  This happens to be me often.  Regardless of what VST I put in.  It's not attributable (as far as I can tell) to any specific VST or VSTs.  It does seem specific to me since this is the first post where I've seen anyone else mention the symptom happening to them.
 
I'm living with it for now.  I have SSD drives and saving and re-opening just takes a few seconds.  But it is strange and didn't happen until sometime in mid 2015.  It's been consistently happening to me every day and every session I work with Sonar since - but I'm still a fan and tolerating it.