I've got a midi clip that I was playing through the synths and both stopped working. 
Exited/Restarted Sonar.  No joy.
Rescanned VST's.  No joy.
Added new DP synth.  No joy.
 
If I assign the midi clip to an external keyboard works just fine. Other aspects of Sonar seem to be fine.  I've got X2.
 
Anybody have any ideas?
 
Thx!
 
Mike F.
www.outspakethebrave.com
A different kind of band.  A different kind of music.  A different kind of mission.

Save the project with  different name, then go to the event list and delete any RPNs or NRPNs. Restart Sonar. Just change the name to Namexxx. You can always delete that if this is not your problem and you'll have your original project intact.