I bought this yesterday. It seemed to work okay when I tested it, but now the top won't lock into place at all, no matter what I do. I tried all different positions, turning techniques, maneuvering and even some calm coaxing and encouraging words. It will not work. I had to chop my onions by hand. If Cuisinart is going to make these impossible safety precautions, then at least share the secrets of them with the customers who pay several hundred dollars for the product! This is going right back to the store it was purchased from. Useless!