There are 2 macs connected to a router, one is called "Mac A", using ethernet cable and the other is called "Mac B" using wi-fi. Mac A has shared its hard drive so that Mac B can see it, but there are "stop" signs on many of its folders apart the "Desktop" folder. So the Mac B user cannot enter all other folders despite file sharing is enabled! What is wrong and im getting "stop" signed folder icons without any access?