Sales Orders can be saved with an Invoice number when the user clicks the Invoice button and then clicks Cancel in the Payment method screen. This is due to the request of many companies than need to provide the Invoice number to their Payment Terminal.

If this Sales Order does need to be cancelled then please use the following steps; 

Step-by-step guide

  1. Delete the line items on the order
  2. Create a Comment Line that says something like "Order Cancelled" 
  3. Post the Invoice

Note: It is not possible to Post a zero dollar Invoice without the Comment.

If your company does not require the Invoice number for the Payment Terminal and would prefer not to assign the Invoice number in the payment method screen, then please disable the setting in;

Company Settings, Sales Orders, Process/Invoicing Allocate Invoice number for payment.