Syncing Issues with Yamaha MoxF6

Since updating to Windows 10 (and now its supported I can ask this question) I have encountered a problem with making the MoxF6 the master for Cubase Elements 8.

I believe I have configured everything correctly on the MOXF6 I have tried Midi sync both set to Internal and auto, external clock on and sequencer control to out and in/out and all the combinations of the above and also checked Midi is set to USB.

whatever the seting in song mode I do not see external sync connecting on cubase.

I have tried MTC time sours set to all Midi and one by one of the 5 Yamaha ports but to no avail.

What is so frustrating is that if I use Cubase as the Master it syncs perfectly. I am pretty sure this used to work fine under Windows 8.1 - but I have tried so many setting changes to try to get it work I might have got something wrong.

Can anyone help. For live work its much better to start cubase of from keyboard than from laptop and have to run back over. thanks in advance for any suggestions anyone can make.

Windows 10 is fully up to date and I have installed the latest Steinberg / Yamaha drivers.