Please review the scenarios listed below and also review the attached video to correct your locking problem.
Position the lock to its full open position. Push the upper sash to the top of the window and move the lower sash to the bottom of the window. Once both sashes are in their proper positions, slide the lock into the “locked” position.
Push the upper sash all the way to the top while at the same time pushing the lower sash down. This will align the lock and will allow you to lock the window.
Tilt both sashes in as if you are cleaning the window. Push both sashes firmly back into the window channel. This should align the sashes and allow the window to lock properly.
If the balance shoe becomes dis-engaged from the sash, the window will not be aligned and therefore not lock.
If the instructions listed here don’t fix the problem, please complete the service form for further assistance!