MIDI playback only plays a single note (A1)

[Amnesiac]

Hello.

I have issues with PT's MIDI note communication. It only plays a single note during playback, no matter how many different pitched notes are edited through the track. For instance, lets say there are 4 quarter notes in a row, C2, D4, E2, F#3. When hitting "play", what sounds is: 4 quarter notes in a row, but they all are A1's. The only note that it sounds during playback is A1, even if there are chords or intricate melodies on the track.

Im Working with Mbox 2 and PT 7.3.1 CS6
This issue affects virtual instruments as well as my sound module. They only play a single note during playback.

This is my set up:

MIDI or Instrument track with MIDI notes on it.
MIDI in: All (or anything from the predefined choices, there is no difference)
MIDI out: any of them

What could it be?? I dont know if there is an internal setup in PT thats causing the tracks to send a single note. Searched through the reference guide and didnt find a thing about this.

[musicalavtech]

If you click on the little keyboard on the left of the track or the playback notes, what do you hear? Did you try the digi troubleshooting methods? Did this occur just out of the blue? Did it work fine with an earlier version?

[Amnesiac]

To answer all of you questions:
1.
If I click on the vertical keyboard one the left, I can hear different notes play as it would normally sound. If I play the midi controller thats connected to the Mbox's MIDI input, notes are played fine as well. But during playback I get only one note.

Furthermore, If I arm the instrument track and record, whatever notes are played during recording on the midi controller keyboard (an axiom 49) sound the same, as A1.

2.
I dont know what you mean by digi TS methods.

3.
Yes, it started happening out of the blue.

4.
Back when I hadnt installed CS6, everything seemed to work fine.

Should I re-install PT without the CS6 update?? I want to avoid that since the CS's are built to make PT work better...