I DON'T UNDERSTAND YOUR QUESTION. I HAVE OP SYS 2.00. INSTALLING THE VOCALIZER DIDN'T CHANGE MY OP SYS. I NEVER HAD THE PROBLEM BEFORE INSTALLING THE VOCALIZER. I BELIEVE THE PROBLEM IS WITH THE CC 91 ON THE HARMONIZER CHANNEL, CONFLICTING WITH THE MJ SYS EX MESSAGE IT WRITES TO THE MIDIFILE.