You can delete Task Types that you no longer need. To delete a Task Type, you must have Close Administrator or Power User security rights.
Note:
You cannot delete a Task Type if any tasks belong to it.
To delete a Task Type:
From Manage Task Types, select the Task Type that you want to delete.
Use one of these methods:
Click Actions, then select Delete.
Click the Delete icon.
Right-click and select Delete.
At the delete confirmation prompt, click Yes.