Simple (?) MIDI problem driving me crazy

I've been working with MIDI for over 20 years and this has been driving me crazy for the last hour.  I've never had it happen before.

I've opened up, in SONAR, a MIDI file that I created in Band In A Box.  Push play and it sounds fine using my computer's built in Microsoft GS Wavetable Synth.

To get a better quality sound, I insert an instance of Cakewalk TTS-1 and point the tracks to it--a separate channel for each track--and I'm hearing about half of the notes.  It more or less randomly (?) just doesn't play some of the notes on a busy picked guitar track.  It doesn't play any wrong notes--just doesn't play some of them.  (Looking at Piano Roll View, there might be an issue with identical notes being played at the same time--except one of the guitar picking tracks is on Channel 3 and the other on Channel 6.  Polyphony and choking shouldn't be an issue, right?)

I've gotta be missing something simple here and just suffering from temporary insanity (which might become permanent if I don't get this figured out).

Although I thought this is now dynamic in X2a, too small a MIDI buffer will cause missed notes amongst other problems. Prefs--->MIDI---->Playback & Recording is where you'll find the setting.

Jerry, Karl has it nailed for you. Your standard midi buffer setting for Sonar is 250. That has never worked for me. On one of my machines I have it set to 1000, on another, 2000. Not a single problem.

Go where Karl said and look for "playback" and set the number in the "prepare using" to say, 800 for starters and see how that works. If it doesn't, try 1000 and then 2000. That should sort you out. If it doesn't, something else is going on somewhere...but we'll figure it out. :) Have no fear.

-Danny