I try to run Nintex workflow with "Copy to SharePoint" action for Infopath form with file attachments. This action should copy Infopath attachments to separate document library. And in case, when status of user, which downloaded documents to Infopath form, is "presense unknown" (for example, for old forms which has been created by fired users), workflow breaks down with error “Failed to copy item. User cannot be found.”. As I understand, error occurs because this action tries to copy system user fields (CreatedBy and ModifiedBy) to copied document.
How to avoid this error during this process?