This problem usually has one of two causes: jammed blades or a faulty motor. Try shining a flashlight down the disposal drain to see if there are any visible problems, like a piece of silverware blocking the blades. If so, UNPLUG the unit and CAREFULLY remove the obstruction if it is safe to do so. If a jam isn’t the source of the problem, the motor may need to be replaced. In this case, it’s often more cost-effective to replace the unit.