A humming garbage disposal is receiving power but can't rotate — the impeller (spinning plate) is jammed by something hard. This is a very common problem and almost always fixable in 5 minutes with the Allen wrench that came with your disposal.
Likelihood: Very common
A bone, fruit pit, bottle cap, or other hard object is wedged between the impeller and the grind ring, stopping rotation.
Fix: Use the Allen wrench port at the disposal base to crank the impeller free. Remove the object.
Likelihood: Common
Celery, artichoke leaves, and other fibrous foods can wrap around the impeller shaft and stop it.
Fix: Same Allen wrench approach, plus use tongs to pull stringy material from inside.
Switch off the wall switch. Unplug the disposal from under the sink (or turn off the breaker). Never put your hand inside a disposal — even with power off — without confirming it cannot activate.
Find the hex socket at the bottom center of the disposal. Insert a 1/4-inch Allen wrench (InSinkErator includes one; if lost, any 1/4-inch hex key works). Crank back and forth — you'll feel resistance then it will loosen as the jam breaks free.
Tip: If it won't budge, apply steady pressure in one direction for 10 seconds before reversing. Don't force it suddenly.
Shine a flashlight into the disposal. Use tongs or needle-nose pliers to remove whatever caused the jam. Never use fingers.
Plug the disposal back in (or restore breaker). Press the red reset button on the bottom. Wait 2 minutes, then turn on water and activate the switch.
Avoid: bones, fruit pits, grease/oil, coffee grounds in large quantities, celery and artichoke leaves, eggshells, potato peels, and expandable foods like pasta and rice. These cause the most jams and clogs.
Frequent jamming despite careful use can indicate worn impeller blades that no longer move objects effectively. If it's 10+ years old and jamming repeatedly, a new disposal is more reliable than ongoing repairs.
Replace the disposal if: it jams repeatedly even with careful use, if the motor overheats frequently (reset button trips after every use), or if the unit is 10+ years old.
ChatDIY can adapt this diagnosis to your exact fixture, tools, photos, and skill level.