Deleting WAITING tasks
Background tasks can be deleted only if they have a Status of WAITING on the Active Background Tasks form. Even then, deleting a task record from that form does not delete the task definition from the Background Task Definitions form.
           Note: When deleting background tasks, keep these facts in mind: 
           
         - To completely delete a background task, you must also delete the task definition from the Background Task Definitions form.
 - You can use the Background Queue form to add a task several times. If you later decide to delete a task on the Active Background Tasks form, be sure to delete the correct task.