i second that… fans are spectacularly complicated sometimes… if it has the push-in screws you gotta push before they’ll catch and you can actually screw ’em in, or if it has a metal clamp across the middle those are general pains in the arse. generally speaking, while still doing it by hand, it may take a fair amount of force to get the fan back in. that said, use of a crowbar is unnecessary and highly discouraged.