- To play back all instruments, select a single note
- To play back only a single staff, select multiple items on the staff
- To play back multiple staves, select items on multiple staves
Then press P to start playback.
Then press P to start playback.
See if you have a Bracket and Barline Change signpost (activate Singpost visibility from the eye icon). If yes, select and delete it (otherwise please upload you Project, to see what is going on):

That was it. Thank you! Strangely, I had a ton of them so might have been imported from the xml.
Thanks so much, that was it. I thought playback and play were the same thing. Spacebar plays tutti but P played the selected instrument. Much thanks!