Thanks Jimbo and Geoff, good suggestions. The interleave is set correct. both the mixdown track and master buss is set to stereo. 

on export try selecting buses as your output.
give it a test run, this will export what your master volume is set at.

thx Charlie. The sound difference is in the bounced track, not the exported output. Now that I turned the machine off, when I boot up tomorrow, it will probably be fine. With my luck.  :-D

I remember that there was a change in panning laws resolution somewhere in the X series. There had been a long time "error" that was fixed. I use quotation marks because I'm not sure what it was all about but I do remember a change. Could that be having an effect seeing as you've started in 8.5.

I sympathise with your myriad problems but I have to say that a long time ago I learned that I need to finish a project in the version in which it was started. It's saved a lot of headaches. It also taught me that a project does have a life span and it needs to be finished. Anything else just goes into a repository of bits and pieces of audio and or MIDI files. That's why I always keep any version which has an ongoing project loaded on my machine.
Once it's done so is that version of Sonar except for what is required for any useful plugins from that version.

I've found that playback of most projects is OK but even then I save it in the newest version of Sonar on my system.

 Thought it was TM too but hopefully you find the cause.
 

Master bus Gain/Volume adjusted in offset mode? Send on the Master in parallel with the output or to a headphone out that's getting merged in Totalmix? Does the Master bus meter show a different level than the track meter?
 
The Pan Law issue was fixed in 8.5.2, and would not account for a difference between direct out and Master bus.
 
 

GuitarMech111The sound difference is in the bounced track, not the exported output. Now that I turned the machine off, when I boot up tomorrow, it will probably be fine.

 
Is it possible that your bounced track is routed to the same master bus as all your tracks and so you are applying all your master bus FX again to the bounced track? Make sure you route your bounced track to direct outputs. Don't let it run to your Master Bus again.

If this is related to the pan issue that was found to be because of Offset Mode. It is possible that the issue listed in this thread may be due to being in offset mode.  

Yep, it was. I think there should be an UPSET button next to that OFFSET button.... ;)
 
Thanks for all the input. Offset mode killed me yesterday...