A door that will not latch is usually misaligned: the latch bolt does not enter the strike opening. Before filing metal or moving the strike plate, check hinges, gaps, and seasonal movement because the cause is often on the hinge side rather than at the latch itself.
See where the latch is hitting
Close the door slowly and see whether the latch lands high, low, or sideways relative to the strike opening. A rub mark on the strike plate can reveal the direction of misalignment.
Tighten hinge screws first
Loose hinge screws let the door sag and shift the latch. Tighten accessible screws without stripping them; if a screw spins without biting, repairing that hinge hole may solve the problem without moving the strike.
Adjust the strike only after the door hangs correctly
If the gaps are even but the latch still rubs, move the strike plate slightly or enlarge the opening only as needed. Avoid removing excessive metal because it weakens the catch and can leave a visible gap.
Seasonal movement may require addressing the cause
If the door only sticks during humid seasons, check for wood swelling, unfinished edges, or frame movement. Aggressively trimming the door in one season can leave an excessive gap when humidity changes.