First thanks for the response and suggestion. It was a driver problem but not so simple.

Turns out the Win 10 update earlier this year screwed up the older Korg driver. Lots of info and regedit fixes on line. However, Korg has since released a new driver, version 31 but it did not seem to solve my problem. (That's when I posted.) While poking around on line some more, I learned that version 33 was available on the Korg Japan support site. Removed the old, restarted, loaded version 33, restarted … all seems back to normal.

By the way, the 4X is a great keyboard but as you probably know if you follow the Korg Forum, many think the 3X is was one of the best they ever made. I moved from the 2X to the 4X so improvements were much more dramatic for me.

Again, thanks.

Ron