This error occurs when the item has been published once already and then deleted in KashFlow.
To ensure that duplicates are not created in your accounting software we put an electronic tag on all items after they have been published. Removing this tag will resolve the issue.
1. Select the items you need to publish.
2. Click the 'Tools' button on the menu at the top and choose 'Clear Publishing Data' before exporting.
3. Now simply click on the green ‘Publish’ button: