Receipt Number is not selected or Item is not listed or has exceeded the limit in the receipt
Returns can be calculated from the stored transactions by using the verify transaction feature from the sale transaction screen. This will allow a user to return all items on a transaction and only items found under the transaction.
Transaction number needs to be selected to enter items for a return, with out a coordinating transaction the system will not let you run a return or add negative items. If negative items are added to the transaction that weren't on the original transaction won't be added; unless it is a positive items for an exchange.