When you click on the Where to back up drop-down list box, you may notice that any USB and FireWire drives installed on your system do not appear in the list. This does not mean you cannot use USB or FireWire drives for backing up your files. It just means that you must select the Hard Disk Drive backup method to protect your data.
This is accomplished by choosing Hard Disk Drive from the Where to back up list. You will then click on the Browse button and select your USB or FireWire device as the destination for your backup file.
Note: USB and FireWire are standards for transmitting digital signals between various devices including external hard drives, scanners digital video camera, and computers. FireWire is also known as IEEE-1394 and i.LINK.