If you ever find a Magento shopping cart is erroneously showing ‘in stock’ items as being ‘out of stock’ and you have ‘Manage Stock‘ set to ‘yes‘ under System > Configuration > Catalog > Inventory then you have probably hit a bug in Magento. There is a fix.
I know this particular bug rears its head when configurable products are created and one or more of its product variations is set to ‘Out of Stock’ and/or the variations are not assigned to product categories.
A product can vary its attributes in any number of ways such as by color, size, shape, material, texture and so on… The base product is the one that product variations are created from. The base product is the configurable product and it is the template product for the simple products that are created out of it.
Definition out of the way, when you create configurable products in Magento, edit each of the simple products created from it:
- Ensure each simple product is set to ‘In Stock’ under the Inventory tab
- Ensure each simple product is assigned to a category
If your products are already created you will need all simple products created from the same parent configurable (base) product to check that each simple product (ie variation) is assigned a category and is not set to ‘Out of Stock’. If even one of them is set to ‘Out of Stock’ under Inventory > Stock Availability then the base (configurable) product will display the ‘Out of Stock’ message.