This was happening with Sonar Professional, so I just downloaded/installed CbB. Thought maybe the old Sonar was the issue.
 
But same thing is happening with brand new install of CbB. Cakewalk plug-ins (SI-Bass, etc.) seem fine. So is Kontakt Player and Sonivox Orchstral companion strings But Slate Drums4. Addictive Drums2. AAS Strum GS-2. Air Music Technology (the DB-33 and Hybrid synth) all have the box grayed out and inaccessible.
 
The third-party plugs seem to work as a simple instrument track okay. But I"m trying to set Slate Drums to multi-track outs into CbB tracks and I can't because I can't enable MIDI out.
 
Any ideas on how I would troubleshoot to find the problem? 

The ability to set MIDI out is dependant on (and set by) the actual soft synth.  Not all support it.  For example, Rapture Pro does not, but Meldaproduction Mpowersynth does.

Yes, most soft synths do not pass through or generate MIDI data. The VST scanner checks for this feature and sets a flag in the VST Inventory for each plug-in.
 
The plug-in's documentation should detail its multi-output implementation.

promidi
The ability to set MIDI out is dependant on (and set by) the actual soft synth.  Not all support it.  For example, Rapture Pro does not, but Meldaproduction Mpowersynth does.

Hmmm. Don't I need MIDI out to send multi-tracks out of say, SSD4, to individual kit piece tracks? I route out of SSD4, say the kick on a mono "out" of its internal mixer, and I set up a track in CbB. That track "sees" the out from SSD4, and I set the track to have that SSD4 "out" as the track "in" but it's not getting any signal? Want to send all the Slate Drum mixer channels out to individual tracks to control in CbB. 

No, "Enable MIDI Output" is used for plug-ins that generate or pass MIDI through the plug-in for use by something else. Multiple audio outputs from a synth have nothing to do with the "Enable MIDI Output" setting.
 
MIDI data from one or more tracks feed the plug-in. The plug-in interprets the MIDI data and the audio is routed to one or more outputs based on assignments made in the plug-in. The plug-in audio outputs are inputs to audio tracks.

scook
No, "Enable MIDI Output" is used for plug-ins that generate or pass MIDI through the plug-in for use by something else. Multiple audio outputs from a synth have nothing to do with the "Enable MIDI Output" setting.
 
MIDI data from one or more tracks feed the plug-in. The plug-in interprets the MIDI data and the audio is routed to one or more outputs based on assignments made in the plug-in. The plug-in audio outputs are inputs to audio tracks.

Okay. Thanks. I’ll keep working on getting multitrack audio out of Slate Drums to audio tracks. Have watched videos on how to do it but for others DAWS. Concept should be the same, just haven’t figured it out yet.

don't use simple instrument track, and insert with "all outputs" (not just stereo)?

Billy86
 
Cakewalk plug-ins (SI-Bass, etc.) seem fine. So is Kontakt Player and Sonivox Orchstral companion strings But Slate Drums4. Addictive Drums2. AAS Strum GS-2. Air Music Technology (the DB-33 and Hybrid synth) all have the box grayed out and inaccessible.
 
The third-party plugs seem to work as a simple instrument track okay. But I"m trying to set Slate Drums to multi-track outs into CbB tracks and I can't because I can't enable MIDI out.

All of the plugins you have listed, except for the Kontakt player and the Drum plugins, will only have one stereo audio output, regardless of whether you insert them as a simple instrument track or with all audio outputs.
 
For the instruments with multi outputs, you should select 'MIDI source' + 'All Synth Audio Outputs'.  If you insert a multi capable plugin with all audio outputs, you will then see all outputs from the plugin in the Cakewalk mixer.  You can adjust your plugin to route parts to designated outputs as desired, and then mix them in the Cakewalk mixer.
 
Signal path:  MIDI track (sends MIDI data to plugin) > Plugin (interprets MIDI data and generates sound) > Plugin audio output > Audio track (in Cakewalk mixer)