Hi Larry, never experienced this problem myself playing a Yamaha file in Sonar, but tend too suspect (like you) that these could be some kind of SysEx or Yamaha exclusive meta events that might be hanging things up. What's odd is that you're not even able to delete these events (horizontal bars). Curious, do these events show up in the 'event list' window as well? Though I certainly don't know for sure, I'm wondering if the events which are hanging up the playback might be specific arranger kb type start/stop commands?

I hope some of the midi experts here might be able to shed some light on this and provide a solution to the problem.

Good luck, - Scott