Due to recent over-heating and fire hazard issues with the batteries of the 15-inch MacBook Pro models, sold between Sept. 2015 to Feb. 2017, Emirates Airlines has banned them on their flights, both as carry-on or checked baggage. 

On another note, new baggage rules have been introduced at Dubai airport in order to improve services for all passengers. The main thing to know if that each bag must have at least one flat surface (no round or irregular shaped items of luggage will be accepted).  Any item of baggage larger then 90cms in length, 75cms in height or 60cms in width, must be checked in at the oversize baggage counter.