The Western Digital Passport provides expanded storage space and backup features for Windows-based and Macintosh computers. Format your Passport so the drive is compatible with the backup tools available in Mac OS X and so it can perform the common task of transferring files between the external hard drive and your Mac's internal hard drive. OS X includes all the tools to format the drive and store files on the Passport external hard disk.
Connect the USB cable from the Passport to an available USB port on your Mac.
Click "Finder" and then click "Applications." Click the "Utilities" folder and then double-click "Disk Utility."
Click "My Passport" on the left side of the program window and then select the "Erase" tab. Click the "Mac OS Extended" option in the "Volume Format" menu, then click "Erase" to format the drive for your Mac.
Use with Time Machine
Plug the cable from the hard drive into an available USB port on your Mac.
Click the "Time Machine" icon in the "Applications" window if the utility does not automatically appear.
Click "Use as Backup Disk" to create a backup of your entire Mac on the Passport.
Connect the USB cable to an available USB port on your computer.
Double-click the "Passport" icon on your desktop to open a folder associated with the external hard drive.
Copy files and folders into the Passport's folder to copy them onto the hard drive. Wait for them to be completely copied on to the hard drive, then click the "Passport" icon on your desktop. Drag the icon above the "Trash" icon and then release your mouse button to safely eject the Passport external hard drive from your computer.