How to Fix a Door That Won't Latch

D Doors that fail to latch properly are one of the most common, yet overlooked, frustrations in a home. Most people simply shove or kick the door shut, which only exacerbates the underlying alignment issue over time. The root cause is almost always a minor shift in the house foundation or loose hardware that has allowed the door to sag just enough to miss its target. Fixing this is a Saturday-morning job that requires nothing more than a screwdriver and a bit of patience. When done well, the door should click shut with a light push and sit perfectly flush within the frame. You are looking for a smooth, silent engagement between the latch bolt and the strike plate, restoring the door's security and insulation.

Tighten Hinge Screws First. Open the door and inspect the screws on the top hinge plate. If any are loose, tighten them firmly into the door frame, as even a sixteenth-of-an-inch sag at the hinge can cause a latch to misalign.
Spot the Sag Pattern. Check the gap between the door and the frame along the top and sides. If the gap is tighter at the top corner away from the hinges, the door is sagging and needs a shim behind the top hinge.
Slip a Shim Behind Hinge. Loosen the top hinge on the door frame side and slide a thin piece of cardboard or a plastic hinge shim behind it. Tighten the hinge back down to force the door slightly upward and away from the hinge side.
Mark Latch Contact Points. Close the door slowly and observe where the latch hits the strike plate. If it hits too high or low, you must adjust the position of the strike plate itself.
File the Strike Opening. Remove the strike plate from the door frame using a screwdriver. Use a wood file to widen the opening in the jamb in the direction of the misalignment, then reinstall the plate.
Secure the Latch Faceplate. Check that the faceplate of the latch itself is flush with the edge of the door. Tighten the two small screws holding the latch mechanism to ensure it is not recessed too deeply or protruding.