This error usually occurs when a task is set to collect data, filter it, create a file, and email the result. If the filter step returns no data but the task is configured to continue processing, it reaches the email step with no file to send — causing the step to fail.
In the task event log, look for a warning from the **Save As File** step stating that the 'Recordset contains no rows' just before the email error. This confirms the task failed because there was no data to include.