I use Pro Tools 12 and am fairly new to midi recording. I’ve recorded drums on several tracks and it worked just fine. I laid down the kick and snare and went back on the same track and recorded the other parts (toms, symbols, ect….). However, I started recording drums again today by laying down the kick and snare. This time when I go back to add in other sounds on the same track, it records over (deleting) the previously recorded drums. Any help would be great.
On the transport, there is a MIDI merge button (lower right) between the metronome and conductor buttons. If it's not enabled, you will replace MIDI data while recording.
If you don't see the MIDI button, set the transport mode to ALL or MIDI Controls (click on the triangle button upper right).