There is a major bug in Magento, which does not affect the Product Quantity Box in the Product Details page in the store. Thats why, when a user goes to a product and adds to his cart, he gets an error message ,and then he has to enter the quantity again in the box. Doesnt that sound to be more pain for a customer ? So, the best way to overcome this issue is hacking the core template file ,so that the product quantity always shows 1. Follow those below steps; Locate: /app/design/frontend/default/your-theme/template/catalog/product/view/addtocart.phtml Open and edit the file: addtocart.phtml Find and Replace: [php]<input name="qty" typ...