Just to make a liar out of me, my Dorico hub opened after a mere 40 minutes.
I had the same problem. Downgraded to 6.11 and it boots right away.
Thanks for all the input Daniel and others. Since eLCC 6.11 works well with my Dorico 3.5.1 on my Windows 10 machine, I will stick with it until I am advised otherwise.
I updated without problem on Windows 10.
I downgraded to eLCC 6.11 and it didn’t work. The eLCC dashboard is taking forever to find my license.
Unloaded it, rebooted the computer again, reloaded it again and now it works. Thanks!