My situation is exactly the same as Arron with some (not all) 2nd story room definitions and floors/ceilings disappearing. I have the Pro 2017 version. I cannot get to the room definition dialogue as none will appear when rooms are clicked on. I have checked to see if all walls are connected and they seem to be. I too have manually created a fairly complicated roof and so don't wish to mess with that. Any help would be greatly appreciated in restoring the 2nd floor room definitions and floors. Thank you!