My Father in Law did the same thing, not once, not twice, but THREE times! He has a rock/gravel driveway and he had the discharge chute on the mower pointed towards the house. The driveway is a good 20-25 feet from the house, but thats still close enough to shatter a window twice, and most recently the sliding glass door. It's the double oane glass, and he shattered the outer pane on the window and left it like that until he shattered the inner pane. He shattered the other pane on the sliding glass door and it currently has only the inner pane. His response was "I still have one more glass to break before I have to get it fixed." I told him to either use the push mower when cutting along the driveway, or to make damn sure that the discharge chute is facing AWAY from the house when using g the riding mower.