The application has a fail safe to prevent a user from accidental exporting an invoice to Quickbooks multiple times. Once a user has exported and marked an invoice as paid the invoice is then unable to proceed with any further modifications or exports. If a user attempts to export a paid invoice the export will process no data and come out blank.
To re-export an invoice first navigate to the Invoices page located under the Transactions category in the navigation menu left of any page in the application.
To help filter the results further you can click the arrow next to the Invoice sub-category to bring up a status list for invoices. Select the Paid status to only show invoices that are paid and need to be re-exported.
After applying the paid status filter click the ‘Edit‘ link next to the invoice.
From the edit form navigate to the bottom of the page and click the ‘Re-Export‘ button.
This will place the invoice back into the Approved status and allow further modification to take place alongside the ability to re-export to Quickbooks.
For more information on exporting process see How to export to Quickbooks.