Yes, you can export a complete list of unfilled positions in a schedule.
- Choose "Export Schedule..." from the File menu of the open schedule window.
- Select the "List of services with scheduled volunteers under each" option from the Layout menu in the Layout Settings pane.
- Make sure the box to "Include unfilled positions in list of volunteers"
- Then go to the "Included Volunteers" pane, click "Include only these volunteers", and then click "Select none".
- Click the Export button.
The resulting exported schedule will contain only unfilled positions.