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After a spill on the keyboard of my unibody MBP 17", the key reports as always on.

Under Windows (BootCamp) and Linux (LiveDVD) I can easily get around the problem by using an external keyboard.

However, when trying to boot into OSX, the system always starts into Safe Mode (as is intended when holding ). This prevents many features from working.

Disconnecting the internal keyboard from the main board will also disable the power switch, which is thus not an option.

Is there any way to disconnect the key on its own or disable safe-boot altogether?

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4 Answers 4

up vote 2 down vote accepted

Try pressing C when booting. It might help you get pass safe-boot. or you can try using a key remapping app.

Resources:

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While c didn't work for me, the threads you posted contained advice on pressing any number of keys to avoid Safe-Boot. OPT worked for me. –  0x90 Jan 13 '12 at 19:46
    
Good! I'm glad I added them then! –  Chillie Jan 13 '12 at 19:54
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I have the same problem, from the same cause: a spill into my MBP's keyboard rendered it completely nonfunctional, so now I have to use an external USB keyboard. If I don't press any keys at all while booting, it always boots into safe mode. So now instead I always hold down the space bar just after the chime and then it boots normally.

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If you can afford it, I would recommend replacing the topcase and keyboard as Apple suggests. If like me, you can't afford it or are open to a hack fix, then read on.

The problem

Yesterday, a little water spilt on my 13" MBP keyboard. I turned it around immediately, drained out the water and used tissue to suck it all up but the keyboard was still acting funny. I turned it off and left it out in the sun for a couple of hours and turned it on again but problems remained. My warranty had run out just a month ago and I knew Apple would not cover this under warranty. I tried to clean the shift keys and left it overnight with some rice on them with hopes that the moisture might get sucked out. Nothing worked. (The rice bit is an urban legend that seems to work with some electronics). Went to the Apple Store this morning and was told that they wouldn't even take out the key and clean it, and that the entire top case would have to be replaced. A total bill of 156 Euros which I cannot afford. I had a USB keyboard that would let me use the Mac for the moment so I decided to try to work out a fix.

Symptoms

  • Boots in safe mode everytime (which I later found out was because the shift key is pressed)
  • Cannot login because password is in lower case or has numbers
  • Cannot boot in super user mode and try to disable keys or override password as some commands won't work in uppercase (I wouldn't recommend this anyway because its super user mode)
  • All text is in caps and numbers are symbols as though shift key is always pressed
  • Audio doesn't work
  • Keyboard viewer would not always show the shift key pressed. The key seemed to get pressed at random

Fix

  1. Hold the Option button down on boot to bypass the Safe Mode ensure a normal boot
  2. At the login screen, plug in a USB keyboard and enter your password to login
  3. Change your password to one that uses all caps and no numbers
  4. Download and install KeyRemap4MacBook .
  5. Use a combination of the functionalities of the Keyboard Viewer and KeyRemap4MacBook to figure out which shift key is the problem. In my case, I found out that it was only my left shift key.
  6. Disable the left/right shift key on KeyRemap4MacBook and click on the 'Reload XML' button to make that take effect.

    If only one shift key was the problem, then you are done. If both shift keys were shorted, then its likely other keys are too. In which case you should probably just replace the entire thing. If you think other keys are not affected, then you can use KeyRemap4MacBook itself to remap the shift functionality to a lesser used key like the Left Option key.

  7. Under System Preferences > Users & Groups > Login Items , add KeyRemap4MacBook as an application that should start on login. This will ensure that your disable/remap of the shift key is active every time you login.

Usage change/Things to remember

  • Remember to hold down the Option key everytime the computer boots or reboots to bypass safe mode. The fix above is at the software level. The key is physically still shorted at the hardware level and will affect boot.
  • Remember that at the login screen, the disable/remap is not active. So your password now has to be all caps and only letters.

As soon as I can save some money, I will get my topcase and keyboard replaced but until then this solution works great with minimal change. Hope this helps!

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I posted this answer to a similar question here: Shift key damaged how to disable at boot

You could enable a firmware password. When a firmware (EFI) password is active it prevents modifier keys during the boot process unless you first disable the firmware password. Apple's KB article detailing this behavior - HT1352

I'm going to assume that you can't boot to your recovery partition, or an installer disc, thanks to the stuck shift key. Typically you would enable the firmware password from either of these options, however it's still possible to do from the OS.

To enable the firmware password while inside your OS, 10.7 or newer:

  1. Enter the following string in Terminal. This enables the debug menu in Disk Utility. defaults write com.apple.DiskUtility DUDebugMenuEnabled 1
  2. Open Disk Utility and choose "Show every partition" from the Debug menu.
  3. Your Recovery partition should now be visible on the left side of Disk Utility, select and click Mount to mount it in your system.
  4. In Terminal, enter the copy & paste the following command to load the Recovery disk image. open /Volumes/Recovery\ HD/com.apple.recovery.boot/BaseSystem.dmg
  5. The Recovery disk should open in a new window, browse to it's /Applications/Utilities folder.
  6. Locate the Firmware Password application and double click to launch it.
  7. Follow the on-screen instructions to enable a firmware password. I would recommend keeping this password very simple and easy for you to remember. The firmware password CAN be bypassed but the difficulty of doing so varies between Macs.

If your version of Mac OS X is 10.6 or older:

  1. While booted to your OS, insert the gray restore disc labeled "Install Mac OS X".
  2. Open Terminal and copy & paste the following command, this will open a window showing the Utilities folder from the system installer. open /Volumes/Mac\ OS\ X\ Install\ DVD/Applications/Utilities
  3. Double click the Firmware Password application to launch it.
  4. Follow the on-screen instructions to enable a firmware password.
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