If you live in a high humidity area or store your mower outside in the rain, that moisture gets into the cable and begins to rust it. The rust continues to build up inside the cable and then it becomes impossible to move it or it only moves a little. Eventually it will become frayed and break. Then you won’t be able to start the push mower because the flywheel brake will be on and the ignition kill as well.
You can try to lube up the cable and see if it will break free, sometimes it will, but in most cases it is better to buy a new one and replace it. Then find a better way to store your mower and out of the weather. A shed or garage is preferred.
The cable is pretty easy to replace and can be done with only a pair of wide jawed pliers. It takes a few minutes to do if everything goes according to plan.
If you don’t feel like tackling this little project, check out or Locations page for a lawn mower repair shop near you to change your safety bail cable on your push mower.