This has already been reported in 6.20 — it happened to me as well.
I’ve just updated to Dorico 6.2. All fine on the Mac Mini, but when I open Dorico on the Windows 11 laptop the hub just shows an empty box with the menu across the top (see screenshot) . When I open a project, everything works as expected. The first time I opened Dorico on the laptop Windows flashed up a security warning, but it disappeared so fast I couldn’t read it. I guess it’s something to do with permissions? It’s not happened since the first time. Any ideas what’s causing this?
BTW …
It happened again yesterday in 6.2.10 after a warning like this:
I was about to upload a Diagnostic Report here, but I first tried reinstalling 6.2.10, rebooting, and everything seems fine now… but there does seem to be something a bit unstable on Windows for some users.
See also here: