In the main menu, you can use Importation/Exportation items. Before that, for export, be sure to choose a correct 'Working period' : only invoices and vouchers in this period will be exported. Once the directory chosen, xml files are imported/exported to it. Try an export to know the list of xml files. A dialog box inform you about failure/success of the operation. Import is not transactional. But if some failure occurs, you can correct the cause and try it again. Datas yet imported will be ignored ; only those which failed on the first time, will be imported.