My setup is:
Cubase 9
OSX
Focusrite 2i2
When the computer was running OSX El Capitan, everything worked well. After upgrading to OSX Sierra, I am able to record and play audio through the Focusrite 2i2 outside of Cubase 9. I am able to record and playback in Audacity with no problem. For some reason, Cubase sees the 2i2 in VST Devices, but no sound in or out.
Is there now a compatibility issue with Cubase 9, the 2i2, and OSX Sierra 10.12.3?
I loaded windows 7 on a virtual machine on the same Max OSX Sierra box using VMWare Fusion. The hardware works in Cubase 9 in Windows. It works poorly due to the limited resources, so this is not a viable solution.