Symptoms
- Latch won't stay closed
- Piece of the latch is visibly broken or missing
- Latch moves but doesn't grip
- Window can be opened from outside without a key
Likely causes
- CommonWorn or cracked plastic/metal latch partsRepeated use over years wears down the latch mechanism.
- PossibleStripped mounting screwsLoose screws let the latch shift and lose alignment.
- PossibleBent keeper or strike plateImpact or forcing the window can bend the part the latch grips.
- Less commonIncorrect latch installed previouslyA mismatched replacement part may not properly engage.
What to do
- Remove the broken latch by unscrewing the mounting screws, keeping the old part as a reference for size and style.
- Take a photo or the physical part to a hardware store to find a matching or compatible replacement.
- Check the keeper/strike plate for bending or damage while the latch is off, and straighten or replace it too if needed.
- Install the new latch using the same screw holes if possible, or fill and redrill if the pattern is different.
- Test the latch closes and holds firmly from the inside.
- For security, verify the window can't be pried open from outside with the new latch installed.
- Lubricate the mechanism lightly once installed for smooth operation.
Tools and parts
- Screwdriver
- Drill (if redrilling holes)
Window sash latchSearch: “window sash latch lock replacement”
When to call a pro
Call a locksmith or handyman if you can't find a matching part or the window frame is damaged around the mounting screws.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.