Recently unplugged my external USB drive and now it won't mount, not seen.

Thought you could use this info about getting FireWire to work!

First, you should always Repair Permissions in Disk Utility before and after any update; I would do that now. If you installed your update with FireWire plugged in, your Mac may not recognize it anymore.

Try resetting your FireWire ports by disconnecting all FW devices, shut down your Mac and unplug it from AC power (wall socket) for 30 minutes. plug it back in and try FW.

If that didn't work, download the combo update from this site (yours may be corrupt), not Software Update, disconnect all firewire + USB devices except keyboard + mouse, Repair Permissions, re-install update, Repair Permissions again + try. Yours is the 10.4.10 Combo update ( PPC, not for Intel systems). Others reading, download the Combo that applies to your system.

If that still didn't get it Zap the PRAM. While restarting Mac hold down the following key combo Command-Option-P-R. Keep holding those keys down till you hear the second start-up chime, then release.

For those of you with Macs that are not PowerBooks or iBooks, a bad internal battery can cause FireWire to not be recognized, so make sure it's good! Also, here is Apple doc.#88338 on getting FireWire to work.

Cheers!
DALE

External hard drive spontaneously unmounted? Try these tips:

NEW FIRMWARE: Try updating your external hard drives firmware, which is available from your drive manufacturers Web site--or just use VersionTracker's (www.versiontracker.com) search function to find it. Be sure to back up your data before applying the update, and carefully follow the manufacturers instructions.

OUT OF iSIGHT: If you're using an iSight camera while you're using a FireWire drive, the camera may be interfering with the drives ability to stay mounted. Try temporarily disconnecting your iSight and moving it to a separate FireWire port. If you have multiple FireWire devices, try using a FireWire hub.

POWER PROBLEM: A faulty power adapter could be causing your drive to unmount. Your drive may not be getting enough juice to stay on, causing the drive to turn off and thereby unmounting it from your Mac. Alternately, the power adapter may not be providing a steady amount of power, causing your drive to turn on and off. Try replacing the adapter. If you can't get a replacement adapter from the hard drive manufacturer, try your local electronics store. Just make sure the adapter you choose has the same connector and input/output voltage. you can find the input/output voltage on the adapter itself.

Cheers!
DALE