I've read some topicson this issue but, can't seem to figure out how make drywall connect and cover the rim joists.
Kevin Catanzaro / Ace Design LLC
It appears that you cut a hole in the floor to make the opening to the 2nd floor. If that is the case then try editing the hole and turn on "Add Drywall"
Bill is the owner and maintainer of SoftPlanTuts.com