Lock up after switching display mode

just installed the new rhino 6 Wip
at the first run the curve commands did not work.
restarted rhino and the curve commands worked
drew a box and cilinder,
changed display mode from wire frame to shaded worked ok
then changed display mode to rendered and rhino viewports went black
nothing except closing the program seemed to work .
not a very good start.
work is needed

Can you run the command SystemInfo please and paste the text it reports in reply here? Thanks!