This blog will assist you in setting up the “Quantity of all products to Zero” in Magento store. Given are the steps of process to be followed:
In Magento Admin Panel…
1. Click on the Catalog > Manage Products
2. To change all products quantity to zero, “Select All” products first
3. Then from “Actions” Bar, Select “Update Attributes” & click on submit
4. When Update attributes page opens, click on “Inventory” from left-side bar
5. And set “Quantity” field to “0”, to make all products quantity zero & save the changes