synfire pro 1.8 doesn't open 11.12 osx (El Capitan)

El Capitan would be 10.11 Do you mean Sierra 10.12?

Do you see the small launch window opening? At what point does it jam?

If installation completed successfully and Synfire refuses to start, you might need to update iLok License Manager (www.ilok.com).

Thanks for the image. So it hangs while "Loading New EZDrummer Device". 

I've never seen a device that would hang Synfire, so this probably hangs immediately after the device was loaded when the plug-in is searched for. If the plugin is a VST and has been moved to another directory, it possibly searches for it forever. This would be a bug.

Can you send me the rack and/or device for inspection? Please email to support at cognitone.com so we can debug this together.

As a workaround for the meanwhile, if this is your global rack, you can move the rack file to another folder, so Synfire will start. Then do a re-scan of all your plug-ins (Playback >> Audio & MIDI Setup >> Audio >> Scan for Installed Plugins (Reset)). Alternatively, you can start the Audio Engine manually (use Spotlight searcgh for "Engine") and do a re-scan there.

This might fix it.

I'm using El Capitan too. No issues here. I'd say it's a particular plug-in that crashes the Engine. 

Please do a full re-scan of your plug-ins as noted above. Then start Synfire again.

The Drones worked fine with Cubase 8.5. I'll give Cubase 9 a try and report back. 

UPDATE: Cubase 9.0.0 crashes on me too. Will try Cubase 9.0.20 update now. If you haven't updated Cubase yet, please also update.

Deleting the VST3 version of the Drone fixed the crashes with Cubase 9 here (CognitoneDrone.vst3 in /Library/Audio/Plug-Ins/VST3).

The VST3 version should not have been installed anyway, as it hasn't been tested yet. Our mistake. Same for Soundcase.vst3 and Sprike.vst3.