I just created a second staff/solo player in my project and entered some notes using my mouse. Now, whenever I play that staff, it starts by playing a chord (or maybe it’s a single low note?). Does anyone know where this chord/note came from? I didn’t enter it, and it doesn’t appear anywhere in print or write mode. Thanks in advance for any thoughts.
This should at least point you in the right sort of direction: Hearing repeated C4 that's not in the score? - #2 by Derrek - Dorico - Steinberg Forums
The extra (low) note may be intended as a KeySwitch, and you would need to use an expression map that filters that out and uses it as a keyswitch.
(And why did Leo’s response, posted at 5:17 local time) not appear in my queue until I had written my own at 8:00 local time? 
)
So weird! I tried deleting and re-creating the part. If I don’t add any notes to it, then the ghost note isn’t played, but if I add any notes, even in the second measure and not the first, the note is played from the first measure. I’m using Halion Sonic SE. The part I imported as MusicXML plays fine with no ghost note.
Why is there a keyswitch that I didn’t insert and which of the 40 or so expression maps filter it out? Sheesh… I’m just trying to write some music here… why all the goo?
Managed to get rid of it by fiddling with Halion and the expression maps… but don’t ask me how!