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Whenever I connect the AC power cord the trackpad behaves erratically. If I disconnect the computer sometimes returns to normal, sometimes not.

Some background:

  • My computer is originally from the Americas.
  • I'm currently using it in Europe with a European charger.
  • It is running macOS Sierra.
  • I modified some trackpad configuration on my other partition that I use for Ubuntu.
  • I already tried resetting NPRAM and SMC and nothing changed.
  • I repaired my disks using the Disk Utility, however I can't use the Recovery Partition. The loading bar appears but doesn't go away. (I have tried waiting over an hour.)
  • The charger was given to me from my employer and it appears to be original and it also appears to be ok (in fact it was still wrapped in plastic as it appeared to be brand new).
  • I don't have a way of testing it with other chargers and I don't exactly remember if it was happening before this charger. (It could have been). - Currently in my battery menu there is a legend saying "Condition: Replace Soon". I just replaced the battery for a new one and still is not working.
  • Sometimes when this happens I run the following commands to recover my trackpad

sudo kextunload /System/Library/Extensions/AppleUSBMultitouch.kext to disable

sudo kextload /System/Library/Extensions/AppleUSBMultitouch.kext to enable

However sometimes a Kernel Panic error appears. - The last thing I noticed is that somehow only when I use two finger gestures I "lose" the trackpad. - A new discovery is that the keyboard also behaves erratically sometimes like ignoring key presses.

So that's basically my story. I don't really know what to do next, also I don't really have a way to replicate the problem. I just know that only happens when the charger is connected. Of course my MacBook is old but is really powerful.

To conclude, I ran Apple Hardware Test (extended) and everything appears to be fine!

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6
  • Battery : Replace Soon, sounds like the battery is the source of the problem. sometimes the battery gets swollen and starts touching the trackpad circuits which may cause unwanted behaviour. try removing the battery and see if there are any changes
    – enzo
    Mar 16, 2017 at 17:05
  • I will try that. However, that would happen when the charger is disconnected, no?
    – villancikos
    Mar 16, 2017 at 17:14
  • yes you're right, i was thinking about a similar problem i experienced before. could it be related to grounding ? have you had this problem using the charger with different outlets (different locations) ?
    – enzo
    Mar 16, 2017 at 17:24
  • I think @enzo got it right the first time. It might be worth replacing the battery (either DIY or taking it into a shop).
    – NoahL
    Mar 16, 2017 at 18:09
  • @enzo now that you mention. It seems like only happens on specific outlets. So that could be true. I will try to replace the battery, however I don't know if this charger will mess up again with my hypothetical new battery...
    – villancikos
    Mar 16, 2017 at 19:33

1 Answer 1

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After much research, trial and error and thanks to others in this amazing community I've found out the reason behind my trackpad and keyboard failures.

The reason is that my MacBook Pro was missing a Cable Bracket inside. Why was that bracket missing is because my MBP was candidate for the motherboard replacement program that Apple did for Early 2011 MacBook Pro related to the Video Card issue (more on this thread so I took it in Mexico City to an "authorised" distributor called iShop and I remember that was the last time I saw the part (as I reckon I changed the keyboard myself after a coffee indigestion).

So I hope my answer help any soul with the same problem!

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  • I'm having the exact same issue as you did. Same circumstances exactly, Early MacBook Pro 15 inch, erratic behaviour of both trackpad and keyboard since the recall and logic board replacement (except in my case it was done by the Apple store). Could you give me some more details about the cable bracket? Where exactly was it missing from?
    – Joe
    Oct 11, 2018 at 21:11
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    Go to ifixit step 5 (ifixit.com/Teardown/…) in there you will see the bracket on the right side (also see my first picture). Having said that, I have to admit that also my Macbook was dented because of an impact on a corner. Both things were causing this. That’s what I think was causing the issue. Only after replacing the case everything was solved.
    – villancikos
    Oct 12, 2018 at 22:30
  • I had a look and the bracket appears to be present and well-secured. But I suppose the issue is something related to the positioning of components within the case. The battery and power are most probably involved. In any case, thanks so much for this helpful info.
    – Joe
    Oct 22, 2018 at 11:10

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