You can't sell a serialized item without a serial number. This is working by design.
If an item's serial number is not currently available you can't deliver the product at the moment. This usually indicates the product needs to be ordered and/or assembled prior to final delivery. In that case you should create a backorder, layaway, or workorder depending on the circumstances.
You will not be forced to enter a serial number on a sales order. You will need to enter the serial number before the product can be delivered (picked up) by the customer.
Whether you use backorder, layaway or workorder for this process is dependent on your store policies. Backorders can be set to 0 or 100% deposit under Manager | Configuration. Layaways should be used whenever payments will be made over time. Workorders allow flexible deposits (or none).
If your business involves serialized products that need to be assembled prior to delivery, workorders is the best choice. The item needs to be worked on (assembled) prior to delivery.
If you are using our Serial Editor add-in for Store Operations, serial numbers can be entered at the time of assembly along with the assembler's ID and a date stamp. Serial Editor runs inside POS or Manager, or can be run standalone on a service department PC. For information on Serial Editor contact our sales office at 800-322-9471.