It happens not too infrequently that after a computer sleep (Windows, maybe Mac too) that Dorico recognizes a MIDI keyboard, still shows it in prefs, but ignores input. Enabling/disabling the keyboard doesn’t fix it, nor adding/removing if possible (e.g. a USB keyboard). Only fix appears to be quitting and restarting Dorico always fixes the issue.
Would be nice if this didn’t happen but not a great hardship, wondering if there’s any other workaround or idea.
In general hot plugging/unplugging of MIDI devices does work pretty reliably. Next time this occurs, perhaps you could do Help > Create Diagnostic Report and upload the resulting zip file here, in case the audio engine logs tell us anything about what’s happening to the MIDI devices.
Just happened again, diagnostics sent via email …
Unfortunately the diagnostics don’t tell me much. I can see that just before your computer went to sleep that one of the registered devices was disconnected, though I can’t see which one, and I think this makes sense, but at least one device reconnects four or five hours later, when I guess you woke your computer up. There’s not enough info at least in Dorico’s own application log to suggest what else might be going on there.