The invention relates to a method for lifting containers (6), all containers (6) to be lifted being connected by means of locks (1). The method comprises the steps of by an external unit (2, 4) requesting a first piece of information regarding if the locks (1) that are arranged on a container to be lifted are locked or unlocked, requesting a second piece of information regarding one or more given requirements that the locks (1) to be lifted and are locked meet. Then said first and second pieces of information regarding the locks to be lifted are transferred to the external unit (2, 4) or to another unit. In the external unit (2, 4) or in another unit it is then judged if all locks (1) that should be locked are locked and if they meet requirements required for the lift. If that is the case, lift of said container (6) takes place. The invention also relates to a system.