Window lock won't catch

Symptoms

• Lock lever won't rotate fully
• Lock closes but window still moves
• Lock catches on one side only
• Cam doesn't line up with the keeper

Likely causes

• CommonStrike plate/keeper misalignedSettling or a slightly shifted sash can throw off the lock's alignment by a fraction of an inch.
• CommonWorn or bent lock camRepeated use wears down the metal cam so it no longer grips.
• PossibleSash not fully seated in the frameIf the window isn't pushed all the way closed, the lock can't reach the keeper.
• PossiblePaint or corrosion in the lock mechanismBuildup can stop the internal parts from moving freely.

What to do

1. Close the window fully and check whether the lock lever even reaches the keeper.
2. Look closely at the strike plate/keeper position versus where the cam lands.
3. Loosen the strike plate screws and slide the plate slightly to line up with the cam, then retighten.
4. Spray the lock mechanism with a light lubricant and work the lever back and forth to clear grit or old paint.
5. If the cam itself is bent or worn smooth, unscrew the lock assembly and compare it to a replacement at a hardware store.
6. Install the matching replacement lock, using the same screw pattern and size.
7. Test locking from both inside and, if possible, gently from outside to confirm it holds.

Tools and parts

• Screwdriver
• Lubricant spray

When to call a pro

Call a locksmith or window repair pro if the lock housing is broken or the sash won't seat close enough for any lock to catch.

Safety