Checking Default Backorder Functionality
Your store allows your customers to place backorders by default. To verify this is enabled:
From your store's Dashboard go to Settings > Config Variables.
Click the Search button located at the top left of the Config Variables page.
In the Name field, enter "back orders" and click the Search button.
Make sure the Value column of the Enable Back Orders row is selected.
Click the Save button at the top right of the page.
Disabling Backorder Functionality
Sometimes once a good thing is gone, it’s gone. If a particular product isn't going to come back in stock, you’ll want to exempt it from our backorder functionality. Here’s how:
On your store's Dashboard, go to Inventory > Products.
Select the appropriate product from your product list by clicking its Product Code.
In the Advanced Info section, on the Stock tab, select the Do Not Allow Backorders check box.
Click the Save button at the top right of the Product page.
Keep in mind that for products utilizing child products, this setting will have to be replicated for any and all child products.
Backordering is a great way to prevent a customer from shopping elsewhere when you’re playing catch-up with your sold-out inventory. Keep shoppers patiently waiting — or not — by enabling or disabling the backorder functionality accordingly.