Can I Prevent Stock from Being Deducted on Unpaid Orders?
When you create your store's payment methods, the advanced settings of the payment method allow you to specify whether orders paid with that method go into the store's New or Unpaid order statuses.
Typically, merchants would use the Unpaid status for offline payment methods like Check or Money order so that the order doesn't mistakenly get processed and shipped while you wait for the funds to arrive and clear.
By default, when an order goes into Unpaid status (and store wide Inventory Control is enabled), the stock for the products in that order are still deducted from your store's inventory. However, merchants have the option of changing this and not removing stock when the order is in Unpaid. Here's how:
After the above steps are complete, the store will no longer deduct inventory from any future orders that go into the Unpaid status. When you move the order from Unpaid Status to New, that is when their respective product stock will be deducted.
Of the four orders:
At this point, the store's inventory for the product reaches 0. Even though there's 4 orders, one of them went into Unpaid status and inventory was not deducted. So now, when you move the order that's in Unpaid status over to the New status, the store deducts inventory for the product; and brings the stock level to -1.
Therefore, you may want to review your inventory prior to moving the Unpaid orders to New status, just to be safe.