The Unattended Service Account is a single account that all workbooks can use to refresh data. It is required when workbook ...

The Unattended Service Account is a single account that all workbooks can use to refresh data. It is required when workbook connections specify "None" for authentication, or when any non-Windows credentials are used to refresh data. To use this account, specify the Application ID that is used to reference the Unattended Service Account credentials.