1. if your report’s data sources do not support authentication – for instance, an anonymous web service, an XML/CSV file, Microsoft Access data source, then use rsconfig –e –u –p to configure the unattended execution account. Make sure to use a low privilege user account. Access to the data sources will be made as that user account.
  2. if your report’s data sources support authentication – for instance Microsoft SQL Server data sources, or other RDBMS, switch to using the one of the other credentials options, as they provide better security.