I just downloaded PianoBooster (Mac) got the MIDI set up and transscribed a piece of piano music with the help of Musescore. I exported that file as midi and got a file with the extension ".mid". If I want to load that file into PianoBooster it is recognized in the folder I want to pick from, but once selected it doesn't show up in the score lines of PianoBooster. Any other MIDI software (Anvil, Notation Player) recognizes this file instantly. Does P.B. require "special" midi files?
piano works with normal midi files... but it's not real smart about deciding which tracks to display (or on which staff)
Do you see a list of midi tracks in pianobooster in the "parts" box? if so, click on them in turn, and hopefully you'll see notes on at least one staff. you can right-click them to assign them to a particular staff