I have been unable to export audio from  one project. The others are fine. Upon attempt, the "hourglass" stays on with no indication of processing. After awhile I check windows task manager to find Sonar (producer expanded X1) not responding. I then close Sonar. At that point Sonar will not open until I complete a computer restart.

Try disabling all FX then retry.  If that works, there is likely a plugin(s) in that one project gumming up the works that isn't included in the others.
 

I'll try that...thanks Steve