Howdy Lawrence,

Sorry to be tardy getting back to you - busy day

The issue does indeed to be centered on how the bank assignments are made in the file, and whether they're actually being communicated properly to your Yamaha. The fact that at one point they were but then that changed is the part that baffles me the most.

My best guess, without having your setup right here, is that perhaps the Bank Select Method has gotten goofed up somehow.

When Musician (or any Notation product) plays a file, it uses the bank, channel, and instrument patch information that it is in the file for each track/staff. If the track/staff has a bank listed which does not have any instrument patches in it in your playback device, then it uses the default GM MIDI patch. This is probably why some of your drum instrument sounds played like piano - the standard drum kit is "patch 001", which is also the same as the acoustic grand piano. If (1) the channel number isn't 10 or (2) the channel number is 10 but there's no drum kit for that bank, then you'll hear that staff/track as piano. Does this much make sense?

So, one thing we can check is the following:

1. Setup/MIDI Device Configuration (the Big One)
2. Right-click on your Yamaha device, and select "Properties"
3. Take a look at the "Bank select Method" (it's about half-way in the dialog box), and see if it's set to "Normal" or if it's set at something else.

Here's where I'm not sure, because I don't have your device. You may need to try testing different Bank Select Methods, and see if that clears up the problem.

Got my fingers crossed ;)
Sherry