greenworks 40v mower handle won't lock into place, it just flops around. how do i fix it?

You need to properly unfold and lock the handle into its operating position. It won't start if it's loose.

1. Stand behind the mower and lift the handle upward.
2. You'll feel it reach a point where it wants to lock. Push down firmly on the locking levers located on each side of the handle hinge.
3. You should hear a distinct click from each side. Give the handle a gentle shake to confirm it's secure and doesn't fold.

IF THAT DIDN'T WORK: Check that no debris like grass clippings or twigs are jammed in the hinge mechanism. Clear anything out and try locking it again.

HEADS UP: Never operate the mower with an unlocked or wobbly handle. Always check it's locked before you start.