Use either of these solutions:
- Select another volume for the source, then reselect the install CD or DVD. If there are no other volumes to choose from, select the Disk Image option, then select the CD or DVD again.
- Quit Network Image Utility, and reopen it with the install CD or DVD mounted on the Desktop.
The box will now appear.
![](http://www.info.apple.com/images/kbase/107997/107997_1.gif)