Yeah I have the basics.    In fact I just created a new project from scratch and Session drummer and the strings MIDI files work just fine in the new project.
 
It's just the pre-existing projects that MIDI sounds don't work in.

hmm..... I notice that if I look under Prefs -> MIDI -> Devices ->  I have no MIDI input or output devices listed.   Could that be a problem?   How do I rescan for or add MIDI devices?  I never had to do this in the past with X1.

Ah ... Very frustrating! I didn't have that problem. It makes me wonder if installation is correct. Have you launched as administrator and registered the software?

Contacted customer support?

I have a problem mentioned here before in which Sonar resets the Ins and Outs for various tracks.  For example, something that should be going to Session Drummer might be going to Fantom, or MIDI that should be going to port C on my MIDISPORT are routed to Console.  This is probably not your situation, but it only takes a second to check.
 
This is a very elusive and bizarre problem but luckily easy (though annoying) to correct.

Maybe this might help
Phone support will be open in a couple of hours.

thanks I'll try that then contact support.  A few days ago, I had to do a full re-install b/c I had a few issues that I couldn't seem to resolve.   Maybe that killed my MIDI stuff. :)

If you go to Windows Device Manager (lots of ways to get there, one is to hit the Windows button, then right-click on Computer, then click on Manage, and when Computer Management opens up you will see Device Manager on the left side - click on it to open Device Manager)
 
Once in Device Manager, check to see if your midi devices drivers are loaded and functional by expanding "Sound, video, and game Controllers".
 
I wonder if your Power Options may be set to allow selective turning off of idle USB devices.
 
Just a couple of thoughts there, 
 
Bob Bone
 

I think I'm getting closer but still have not found the answer.    On this particular project where I'm having the SD problems - the Output is NOT set to Master.   On all my other projects that DO work, the SDrummer output is routed through to the Master bus.    
 
Problem with this one -- the Master isn't even listed as an output option!    Why is that?

You can't choose a bus if it causes a bus loop. For example, if you route Bus A to Bus B, you can't output bus B to bus A. Bus A will not show up in the list.
 
You cannot output a midi track directly to a bus. It MUST go to a midi synth.
 
All audio tracks should be routable to any bus or Interface Output.

But all of my other projects - SD is routed this way IN: Midi OMNI - Out: Master.  and they all work fine.