Yes sometimes I do run as administrator. I’ll refrain from that in future.
The mystery deepens: in order to rule out the Cubase software being the core problem, I copied both C11 and Dorico onto a flash drive and installed them onto my bog standard Viglen PC that is running W10 20H1 and it loaded fine in both cases. Which was nice, as I was finally able to see what Dorico looks like!
Last evening I checked the e-licenser (dongle) on said Viglen and it was fine - listed all my licenses no problem and ran C11 to confirm. I also installed the original dongle I had with C4 Studio and that also showed up fine in the ELCC although it is now an empty ‘spare’.
You are correct in the message popping up when I tried to start C11 Tuesday night. Hence I knew I had yet another inexplicable problem and went into meltdown thinking I had now mysteriously lost all my licenses as well as my wits.
OK, update: I looked at Steinberg Support and the upshot is by running download manager it would appear the matter has been resolved. Why it all got lost in the first place remains a mystery but hey ho.
Now to sort out Microsoft…!!