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On my Macbook Air A1466 the shift key seems to be constantly pressed, even during boot so it only boots into safe mode because of this.

The issue exists both before and after replacing the keyboard with a brand new one!

This is what I've tried:

  • Reinstalled MacOS
  • Replaced the whole keyboard (painful process)
  • Reset NVRAM (alt + cmd + p + r) during startup
  • Hooked up an external keyboard (this one works fine, but shift is still held down)
  • Tried Keyremapper: https://pqrs.org/osx/karabiner/ which helps WITHIN the OS, but not during boot

Any ideas?

PS: This is not a duplicate of Shift key damaged how to disable it at boot?. There it's simply a keyboard hardware issue, which is not the case here since the keyboard has been replaced.

Semicolon
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    If the shift key is constantly pressed, something is shorting the circuit trace for it. To diagnose, disconnect your keyboard and plug in a USB keyboard. If the problem goes away it's something to do with your keyboard (again) and not the system – Allan Jun 01 '18 at 12:31
  • @Allan well I replaced the keyboard after this issue and have the same issue with the new keyboard.. So is the short circuit on the motherboard? – Semicolon Jun 01 '18 at 12:55
  • We won't know until you start diagnosing. – Allan Jun 01 '18 at 13:05
  • @Allan with the internal keyboard disconnected the issue doesnt occur. Is it worthwhile to replace the trackpad and/or cable? The trackpad has a module that controls the keyboard and the trackpad cable is also responsible for the keyboard data – Semicolon Jun 01 '18 at 14:47
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    Because the computer operates correctly with an external USB keyboard, you know that something connected between the built-in keyboard and the computer's main logic board contains a short. You can replace all of these components, or try changing one bit at a time to see what specific part contains the fault. I'd start with the cables, as I presume they're cheaper and their flexibility itself is a possible fault source. – DavidRecallsMonica Jun 01 '18 at 14:49
  • What @David said. But understand, the keyboard is a USB device, so it's unlikely (not impossible) that it's a cable. I would try removing the battery, and disconnecting the track pad. The battery may have swelled putting preassure on the keyboard and/or the trackpad causing issues. Disconnect everything and test the keyboard in isolation. – Allan Jun 01 '18 at 15:14
  • Before you replace anything, you need to determine what's causing the issue. Disconnect the track pad, reconnect the keyboard and see if the issue goes away. If it does, it's the track pad, if not, there's more diagnostics you need to do. If all you have connected is your keyboard and problem persists 1) verify you didn't install the old one and 2) swap it out for another. – Allan Jun 02 '18 at 05:28
  • @Allan with the trackpad disconnected, the internal keyboard is diconnected as well, so it's difficult to isolate internal keyboard issues. Anyway, the after replacing the trackpad the issue is fixed fortunately. – Semicolon Jun 03 '18 at 10:49

1 Answers1

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The issue was fixed after replacing the trackpad module.

Semicolon
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