Hello Simon,

I ran the last tests you suggested.

When the MIDI Input Driver is enabled and the selected MIDI Output Driver is:

- the CVP-307-2: the melody track plays a different piano sound than when the MIDI Driver Output is on the CVP-307-1, but this doesn't change the problem: Band in a Box 2025 stutters after a few moments.

- the Microsoft GS Wavetable Synth: the melody track plays a barely audible piano, but this still doesn't change the problem: Band in a Box 2025 stutters after a few moments.

I stick to my current conclusion: since Band in a Box 2021 and its 16 new tracks, Band in a Box's handling of the MIDI Input Driver has changed, and this change is incompatible with the MIDI handling of my Clavinova CVP 307.

Best.

PS: Initially, I did not have these two lines CVP-307-1 and CVP-307-2, but only one line CVP-307. Why did these two lines appear and how to return to the initial situation?

Lazy Bird