I run into this a lot. I open Cubase, load a session, then realize I forgot to power on my keyboard. If I power it up after Cubase is already open, it receives no MIDI input. The only solution I’m aware of is closing Cubase, turning on the keyboard, then opening Cubase. I was just hoping someone knew of a trick to avoid the closing and re-opening process.
the trick is to buy Cubase 9, where that has been fixed,
Wow! That alone may be worth the upgrade! Thanks for the tip!
Yeap Cubase 9 has the answer you need.