It's probably just that he doesn't understand why he's allowed everywhere but that ONE ROOM. It's the kitty curiousity coming out in him. After a time of living without permission into that room, he'll stop scratching. Ours aren't allowed into the bathroom, and at first scratched to get in, but have since decided it's not worth their effort anymore to complain about it. The only other rooms we close are our bedroom doors when we're sleeping, and they've even gotten used to that. Hope that helps!