The crate does not move, and its acceleration is zero. Although it's very convenient to treat the effects of friction as a force, and that process usually describes reality quite well, friction is not a real force, and it can never act like a force that's greater than the net applied force. If it could, then we could set a heavy crate down on sandpaper, and use it to generate electricity while it scoots around in response to the large forces of friction under it.