I never got anywhere with this and was largely just giving up on it as I have Logic which quite simply Never once has failed. I accept it’s not the same kit but has never once been an issue.
I’ve raised ticket after ticket with Steinberg and the advisers just dole out the same thing over and over, Update the Driver, Uninstall and reinstall Cubase>
I got it to load this evening after over 2 hours being patient.
Then out of the blue both Headphone sockets worked but only giving feedback via microphones, as in I could hear the Television through either socket but unable to hear any music from iTunes.
I’ve rebooted the computer and now back to square one - Nothing
N.B. it will only open in Safe Mode and I Disabled third party plugins to see if that will help but sadly Nothing. Interestingly, when it did open, it was showing my monitor etc and then two versions of my UR816C offering one that states High Precision???