If only the grasshopper button is selected, a definition is opened (meant to bake elements to rhino) it will fail / stall. if you select rhino first, and then grasshopper it works. why wouldn’t it work when only opening gh? doesn’t rhino have to start in the background for grasshopper to work or even for RiR to work?
Activate RIR (per the Rhino button on in Add-Ins tab)
Open GH (through the ribbon button that appears when RIR initiates)
Open Definition (contains components to bake selected category into Rhino)
Stall (transluscent overlay with spinning circle cursor)