from the Data Backup User Manual page 32 : You may backup to CDs and DVDs by utilizing Apple’s DiskBurn technology. Simply insert a blank CD or DVD while at the Finder, then you will be asked to provide a name for the disk. After providing a name and clicking OK, a representation of the disk will appear on your desktop. This representation will be a valid Backup destination for Data Backup. Simply select this disk representation from the destination well and perform your backup as if the disk were removable medium as described above. After the backup operation is complete, you are free to eject the CD/DVD icon from the desktop, at which time you will be given an opportunity to commit the data to the actual disk. This method no longer works on OS X 10.4 (“Tiger”). Instead, make and mount a Disk Image (.dmg file) using Disk Utility, backup to that and then burn the disk image file to the CD/DVD.