Verify that you have all the necessary FireWire extensions in the Extension Manager and that they are enabled.
To check for the version and status of your FireWire extensions, perform the following steps.
Note: FireWire Disk Support is not necessary for the CardBus or PCI adapter
Click on the Apple icon at the top of the screen and then "Control Panel".
Then click "Extensions Manager". The extensions are listed in alphabetical order.
FireWire Enabler 2.3.3 or higher, FireWire Support 2.3.3 or higher, and FireWire Disk Support 1.0.1 are required to properly support a Western Digital FireWire hard drive.
Required FireWire Enabler and FireWire Support versions depend on the installed operating system (OS) you are using. Make sure you have the latest version for your OS. If you need to know what version your system and OS support, please check with Apple. The Western Digital CD installation process installs FireWire Disk Support.
If the extensions are correct, the next step is to reset the FireWire bus. To do this, turn off the drive and remove the FireWire cable. Turn the drive on and make sure that the drive is spinning (the green light is on). Allow the drive 20-30 seconds to spin up completely and then plug the FireWire cable into the drive. The drive should mount to the desktop.
If the drive still doesn't show up, disconnect the FireWire cable and turn the drive off again. Reboot the system and turn the drive back on. Wait until the System is completely booted up before plugging the FireWire cable into the drive again. The drive should mount to the desktop.
Note:For complete instructions on the operation of WD FireWire Disk Utilities and extensions, refer to the Disk Control manual or WD Software Guide. One of these PDF documents are installed on your system from the WD FireWire Setup CD-ROM.