Freeze Synth results in no audio

[norfolkmastering]

I often use freeze synth to reduce the load on Sonar when I have a busy mix.  It usually works fine.

Today I used freeze synth on an organ soft instrument and got only silence instead of the normally displayed audio waveform. 

Anyone know what might cause this and a fix?

[Amberwolf]

Does the track correctly include when you do a non-realtime-export?  If not, it might ebe a synth that doesn't respond well to fast bounce function, and you might have ot temporarily turn that off when you freeze it (IIRC in freeze options) so that it does a realtime freeze, which is essentially the same as playing it back live and should work normally.