I'm sure this applies to freezing other multi-out synth setups as well (Kontakt etc). But I don't freeze stuff that often. 
 
I have an instance of Geist which has 7 active engines, each one going to their own audio track. But when I try to freeze these tracks, nothing happens. If I try and freeze the instance of Geist from the synth rack, again nothing happens. There appears to be no way to freeze these Geist tracks. Any ideas? 

I don't use freeze so can't be much help. But you could always render each output, and archive the VSTi so it doesn't take CPU power...but you can bring it back if you need to edit. My understanding is that freezing is basically just a special case of rendering.

Yeah I thought about rendering too and I guess if all else fails that's what I'll have to do - I was just wondering why Sonar won't freeze these tracks. They're not buses, and they have a freeze button. 

Simple instrument or audio/midi?
Is this something akin to the issues some (Konrad) have with EZD2?
I have to freeze EZD at the track level, but you've tried that.
Did you have the audio and midi selected?
Tom

There is one Simple Instrument Track from my original insertion of Geist (don't know why I left the SIT in but there you go - I guess I originally inserted it that way to play around with Geist, and subsequently set up the multi-outs once the project progressed). I could of course have just loaded it into the synth rack and created the audio outs). The other tracks are audio outputs from Geist. There is no MIDI - all of the drums are sequenced and arranged within Geist. But all of those synth outputs have plugins on them and I'd like to freeze them. But it's just doing nothing. My only guess is that this is something to do with the fact that everything is sequenced in Geist without the use of MIDI tracks. But still, I did expect that during the freeze process, Geist would do its thing as usual and Sonar would create the audio for each track. 

I gave up on trying this but am now inspired to figure a workaround since it's not just me

What happens when you select the Geist only track and bounce?
T

Same thing as selecting the audio outs. The freeze button is there, but clicking it does nothing.
 
I think we should be able to freeze a synth like Geist. It's not uncommon to have 7 or 8 engines running in a project, each with 16 drum pads of up to 8 layers of samples, and every one of those layers in every engine can have their own effect chains applied to them. It's a potential resource hog.

dubdisciple
I gave up on trying this but am now inspired to figure a workaround since it's not just me

Glad it's not just me either!

If there is no data in the MIDI track, there is nothing to freeze. Try putting a note at the end of the MIDI track, then freeze.