In spite of the good intentions behind the software, a number of users are reporting that their notebook and desktop Macs' FireWire ports have ceased functioning properly or have begun exhibiting other issues. According to MacFixIt, the problem surfaced with Apple's recent printer driver updates as well as the latest QuickTime update.

Per the article, the problem seems to have persisted through several Mac OS X 10.5.x ("Leopard") updates. Sometimes the bug knocks out all FireWire connections, other times it just seems to affect FireWire 400 ports only, leaving FireWire 800 ports working until the FireWire 400 ports are given significant load.

The current fix suggestions are as follows:

-Reset the FireWire controller Shut down the computer and unplug all peripheral devices, and let the computer sit for 3-5 minutes. Then start the computer back up and plug in the peripheral devices again, one at a time.

Quit processes Launch Activity Monitor and force quit these processes:
socketfilterfw (this is the computer firewall)
SystemUIServer (this should restart after quitting)

This fix has reportedly worked for one user, who was able to regain the use of his FireWire 400 ports after quitting the previously-listed processes. Since the first process listed is the FireWall, it could be that the firewall is interfering with the FireWire bus, since FireWire can be used for networking. Users might also try turning off the firewall option in the "Security" system preferences or removing the FireWire ports from the "Network" system preferences.

Other fix suggestions are as follows:

Reset the computer's PRAM, fix permissions, and other standard procedures If nothing else works, reset the PRAM and use Disk Utility (located in /Applications/Utilities to run routine permissions fixes on the boot drive. It may be that the FireWire port is broken, but these standard fixes might help before taking the computer in for servicing.

In order to reset PRAM/NVRAM, shut down your Mac, then start it back up while immediately holding the following keys: Command, Option, P and R. Hold the keys down until the computer restarts and you hear the startup sound for the third time.

We'll have more on this as it becomes available and if you've seen this on your end or worked out a fix for it, let us know in the comments or forums.