I posted about this problem (might have been on the old board). It's not closing the program Noel, it's File>Close to close the current project and so as to open another. I get the spinning wheel hang and have to close the program using the big red X in upper right hand corner. To be clear, I can close CbB without a hang but I cannot close the current project while still leaving CcB open.
Only MIDI hooked up is a Mackie Control connected via mio MIDI to USB adapter. Could that be the culprit?
I'll try your suggestion, and report back, Thanks!