Strangely, when I export a large project to MIDI, I only get the first staff as output. (Flutes.) XML export in contrast exports the entire score.
I’m only experiencing this with a single large, multi-flow project file. A simpler project was able to export all tracks to MIDI as expected.
Is there something I’m unintentionally doing that limits which staves are exported?
I just tried a MIDI export and I find all the instruments are exported on their own staff. I confess the project I tried this on is one-flow project. And I did not come across a type 0 or 1 MIDI file choice (at first, reading your post, I thought about that…)
Maybe someone has tried with a multi-flow project and gets the same behaviour Michael has experienced with his large project? I will try that now…
[Edit]
Well, I just tried with a quite large project (1h20 opera vocal score with many different singers) and each flow got its players. Maybe there is a problem with your project then.
Update: I just tried deleting all flows but one, but am getting the same results. 
Michael, can you zip your file and upload it here? (Without violating copyright issues, of course…)
Workaround: I exported to XML and re-loaded the result into Dorico, then exported to MIDI. This time I got a full score .mid file, as expected.
This is suboptimal in that I’ll lose some information along the way that might be relevant to a standard MIDI export - for example, accents. I’d still welcome suggests as to what could fix the original behavior.
(Thanks for running those tests, Marc.)
Estigy - I’m sure I could send it directly to an individual but the producer probably wouldn’t want me uploading it to a forum.
Are you sure you were not choosing to export e.g. only the Flute layout when you were setting up the export?
I don’t appear to have been given that option. There was a screen that allowed me to select which flows to export, but nothing evident beyond that.
Send me the project, then.
Done!
Daniel, I thought about the Layout export too, and was surprised to notice we had no (apparent) option to export a singular Layout as a MIDI file. I would not need it but for the sake of complete information I felt it was worth noting it.
Picking up this thread. The last I heard from this (from Daniel in email, 4/2/18):
“You’ve uncovered a bug here – Dorico is silently choosing the first layout from the Layouts panel and only exporting the instruments in that layout. We get away with this for most users because the first layout at the top of the list is usually “Full Score”, but in your case it’s the flutes. Temporarily drag an appropriate full score layout to the top of the Layouts panel in Setup mode before you export your MIDI file and you should be all set.”
This bug still appears to be in place. Are there any workarounds other than dragging a layout to the top before each MIDI export?
Not really, no. It’s still working like that. Does the solution present a problem? Any reason why your FS can’t sit at the top of the list?
Full score export doesn’t seem work correctly either: some instruments are merged onto the same MIDI tracks, requiring that their MIDI data be manually separated. This seems to happen if there are more than a few instruments in project, though I haven’t been able to better understand the behavior.
As things stand, if I have ten instruments which I want to export as individual MIDI tracks, I have to create a layout for each one (if I didn’t already have one) then manually shuffle each one’s layout to the top of the list, then do a separate export. If I edit the score and need to export again, I have to repeat the process.
Instruments are only merged into a MIDI track if you, well, send them to the same MIDI track in Play Mode.
And can you tell us about your workflow? Why do you need a MIDI file per track, instead of a multi-track MIDI?
That’s good to know — it might help me separate them by duplicating MIDI output channels to force creation of separate MIDI tracks. I’ll give that a shot next time. Thanks!
I don’t need multiple MIDI files per se. What I ultimately need is for each Player to be output to a separate MIDI track. Prior to knowing the above workaround to the merge problem, the only way I could accomplish this is was manually export a Layout for each player to a separate MIDI file. If your workaround addresses the issue, this won’t be necessary.
All that said, this is still a bug (quoting Daniel) and I hope it’s addressed so that other people don’t spend time struggling with this issue.