diff --git a/gnucash/gnome/dialog-invoice.c b/gnucash/gnome/dialog-invoice.c
index 187972b80c..043666fff7 100644
--- a/gnucash/gnome/dialog-invoice.c
+++ b/gnucash/gnome/dialog-invoice.c
@@ -1764,7 +1764,7 @@ gnc_invoice_update_window (InvoiceWindow *iw, GtkWidget *widget)
                                           gncInvoiceGetActive (invoice));
 
         time = gncInvoiceGetDateOpened (invoice);
-        if (!time)
+        if (time == INT64_MAX)
         {
             gnc_date_edit_set_time (GNC_DATE_EDIT (iw->opened_date),
                                     gnc_time (NULL));