Right hand side loop button lights out?

I have just purchased a MC4000 which I am well happy with. it was running fine with 100% functionality but when I turned it on the other day the right hand side loop button lights were not illuminated, even though they still had functionality. first step was to reinstall the drivers which seemed to work but after a couple more boot ups it did the same. The only thing that has happened with my PC since installing my Denon is a windows critical update so whether that had had something to do with it I don’t know? what I do know is it very frustrating, any advice would be greatly appreciated.

Which software are you using it with?

Make sure that you have install the latest firmware update. It is located at the Denon DJ website under downloads at the MC4000 Page.

I am using serato dj full version and I have already tried updating the firmware which worked for a little while then reverted back to the fault