Why does my garbage disposal hum but not spin?

A humming disposal that will not turn can be jammed, overloaded or worn out. Stop using the switch rather than letting the motor hum continuously. Turn off and disconnect its power before checking the manufacturer's instructions for any approved reset button or unjamming socket. Never put a hand into the disposal, even when it seems off. If the unit trips again, leaks or will not turn freely, the problem may be a failed motor or an obstruction that needs professional help. A plumber can inspect the disposal and its drain connection without assuming you need a new unit.