Invoices should also reflect a due date, Credit memos do not. Didn't know if you were checking this field value as well. If aging is based upon invoice due date this field value could play a role in the error. Another thing to do is to preview the aging then with the error on screen check the company database to see if the temporary work file generated (AP_AgedInvoiceWrkuuu#############.m4t, wrk followed by user code and 12 numbers). If this file exists, leave the error up and access the temporary work file created through datafile display and maint to see which invoice record was the last to populate. Safe to assume that either this record or the next record in line would be the one creating the error.