WRONG. there was never an issue with duplicate numbers in the past, why mess with something that works. Ther is a glitch in this system. I have already done that and there is still an issue, solve it by giving the option to turn it of or on. It should be a choice because it doesnt work as it is. I create an estimate, then convert it to an invoice, it turns on the custom invoice number feature. then it creates number that is in sequence, then says it's already been used. How can that be if it has the number that is in the correct sequence? Why does it work correctly when I go to the old layout? I received a notice that the switch back option goes away on December 11th. Do you understand that this will shut down QBO? If I cant switch back to the old layout, it will prevent me from crating invoices. I have entered in different invoice numbers, and it tells me they have all been used. how is that possible? No matter what number I put in it says its been used.