Sending MIDI data to a record-enabled MIDI track while Pro Tools is chasing timecode, or cueing a deck using MIDI Machine Control, may result in no MIDI data being recorded. To successfully record MIDI, assign the record-enabled MIDI track's input to the specific device (port) from which you want to record, or refrain from playing connected MIDI keyboards (or controllers) while Pro Tools is cueing a deck using MIDI Machine Control.