Could you try saving the game during the black screen and loading it again?
tried it several times:
with new named save game and
with quicksave
in both cases the system does not save the game resulting in no option to load any not-saved-blackscreen-save-game
tested with Hotfix 28,
Edit: tested with full admin rights for bg3.exe and bg3_dx11.exe. In black-screen mode I can manage game options, but saving the game does not work. Loading an old savegame does work though. Also tested to invite a friend, and this time my friend gets the black screen too with the same bugs as mentioned right now. This is getting ridiculous...
soooo: still the same bug.
Waiting for next Hotfix / Patch... this is really frustrating!
