Hello Alyssa,
I understand that you were trying to use the Invoice Volume report/Sales Order Volumen report to figure out which customers were inactive. In reports, be it standard or custom reports, the value # indicates 'unassigned'. So in either of the above mentioned reports, you can pull the following characteristic - Customers, Sales Orders. Invoices into the report pane, then select a time frame of your choice and then execute the report. If there are no associated sales orders, invoices for the customers then you can see # corresponding to those records.
Another way of doing it is try if you can filter for # value for the sales orders or invoice characteristics from the Selection screen or from Edit Filter tabs.
Thanks,
GowriShankar
