Was working in Rhino 6, closed after I finished my file and it wanted to install an update for 6.12. I’m assuming this is the RC. After about 15 minutes I’m still at the point seen in the image below.
Update: I forced closed through task manger because the close on the window wasn’t working. Rhino 6 launches as (6.12.18351.21491, 12/17/2018) so I guess all is fine.