Ive only just upgraded to Cubase 9 in the last few days but this has happened to me twice now.
I’m using version 9.5.30 on Windows 10 (64 Bit) with a Focusrite 18i8 (latest drivers)
If I send multiple audio tracks to a group track (shift+alt) I suddenly get no audio output from the stereo output then when I check the Audio Connections Settings my sound card is available from the drop down menu but does not switch when selected.
My sound card is selected as the ASIO Driver but the Mon 1 & Mon 2 output are “inactive”.
It’s worth noting that the input device is appearing as normal.
Both times this has happened it was while I was routing multiple audio tracks to a group by holding shift+alt and clicking the Output Routing.
I’m going a bit nuts now…