DIAGNOSIS Grease has solidified in the filter frame or the filter latch mechanism is jammed. This is a routine maintenance issue.
FIX Press up firmly on the filter and pull the front edge down. It's a spring-loaded latch. If stuck, use a putty knife to gently pry the front edge down while pushing up. Wash the filter in hot, soapy water.
IF THAT DIDN'T WORK The metal filter frame may be bent. Inspect for bends. Carefully straighten it with pliers. Do not force the filter back in if bent.
HEADS UP Clean these aluminum mesh filters monthly. Do not run the vent without the filter. Dishwasher cleaning is not recommended; it can warp the frame.