Unwanted (extra) Mighty Mouse clicks

[Monday, January 28th]

We previously reported on an issue in which Apple's Mighty Mouse registers an unwanted click -- usually button 4, which is designated (by default) to trigger the Dashboard function. This problem can be obviated by turning off button 4 in the Mighty Mouse pane in System Preferences, though the attached functionality will obviously be lost.

There is some speculation that this issue may be caused by some sort of electrical interference, and indeed some users have had success moving their Macs to a different location, or plugging them into different outlets that are isolated from other specific electronic devices.

We've now received reports that the problem may be caused by externally powered FireWire drives.

MacFixIt reader Manfred writes:

"My unwanted clicks seem to occur when I have an externally powered firewire drive attached. It manifested itself when I was using Time Machine for the first time. Power off the external drive and the unwanted clicks cease. In fact when connected I can actually hear the unwanted clicks happening!"

Relocating other electrical devices, including lamps, can also resolve these issues in some cases. A poster to Apple's Discussion Boards, Josh Oliver, writes:

"I discovered that the light that i had on my desk (some odd novelty lightning lamp) caused the problem. the mouse would act odd when the light was on and only then. if you have any issues with the mighty mouse clicking the 4th button at the slightest touch, relocate any electrical device near the mouse until you find which one it is. apparently the mouse receives interference which triggers the buttons."

Some users have found that discharging static electricity by touching a metal object before interacting with the Might Mouse can resolve the issue.

Finally, high humidity appears to be a causal factor for unwanted clicks.

Feedback? Late-breakers@macfixit.com.

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