Could be a couple of things: 1) there are orphaned records in the SO Invoice Header and/or Detail file; 2) there are Work Tickets with their Being Invoiced flag not equal to Blank (JT_WorkTicket.m4t file, field 47). Delete orphaned records in invoice files if there are any. If none, then identify the open WT's with their Field 47 <>"""" (you will need to create a Crystal Report or an Excel Query to identify any Step 000 Work Ticket records with that value <>"""").