Setup a sequence with AD, Insert LP-64 Multiband (default Mastering Lighter preset) in the Master bus and AD goes silent.  If I turn off LP-64 Multiband AD is fine.
 
Any Thoughts?

I did this as you said and had no problem. AD worked fine when I turned the LP-64 on and off.

I tried it and no issues. 

meh
Setup a sequence with AD, Insert LP-64 Multiband (default Mastering Lighter preset) in the Master bus and AD goes silent.  If I turn off LP-64 Multiband AD is fine.
 
Any Thoughts?

This may be project specific.  Does it happen in brand new projects?

Dan Gonzalez [Cakewalk]
Does it happen in brand new projects?

Yes this is a new project....
This was not a clean install it was an upgrade X2 worked like a champ.  Maybe I should try a clean install.
 
thx

It's still a clean install. Any Sonar installation does not depend on any files that are on your computer related to a previous version. Some plugins are shared across version but nothing in the core program. On installation, Sonar reads settings from your most recent version and applies them to the new version.

Possibly a MIDI buffering issue because LP-64 introduces PDC? Try setting your MIDI Prepare Using buffer up to 500ms if it's not there already.
 
And/or do you have any MIDI FX in the project (not just on that track)? They can also introduce some buffering issues.

brundlefly
Possibly a MIDI buffering issue because LP-64 introduces PDC? Try setting your MIDI Prepare Using buffer up to 500ms if it's not there already.
And/or do you have any MIDI FX in the project ... No

MIDI Prepare Using buffer that was it....thanks