I have a macbook 12'' running sierra that I use occasionally.
The battery died some time ago, showing an X in the status bar.

I want to update to a new version of macOS but the installer shows:

Your computer is not connected to a power source. You must plug in and connect your power adapter before installing.

Obviously the device is connected to the power source (the battery is dead).

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I have already done the SMC reset. Didn't help.

Can I convince the updater to install despite the fact that it thinks I am on battery power?
Can I convince the system to recognize my power connection as an actual power connection?


Well baring the obvious and replacing the bad battery you will probably have to install the OS on a different computer and reinstall the hard drive. The Mac power module is not responding that the laptop is connected to AC but responding that the battery is bad. Apple will replace the battery for $199 so keep that in mind while doing any work around.

You can also put this MacBook in USB target mode and run the installer from another Mac to perform the upgrade without fixing the hardware. The battery service there is relatively labor and parts expensive due to the thin assembly, delicate cabling and glue that makes the cells part of the case structure. You’re getting a partial frame replacement when the battery is exchanged for $200 and possibly new top case / keyboard if the cabling or parts don’t fit when it’s out for repair.

  • I love the 12 MacBook but don’t expect there’s a viable way to get around this check other than having another Mac run the upgrade. +1 answer to a +1 question. – bmike Jul 28 at 22:40
  • thanks for "target mode'"- unfortunately no other mac let alone usb3 adapter at hand! – de. Jul 29 at 11:26

I have finally gotten around this without battery replacement (will do another time, not an option right now):

  1. Use Disk Utility to create a second partition
  2. Make the second partition a bootable installer
  3. Restart the computer while holding 'ALT'-key to choose the start volume
  4. Chose the new volume with the installer
  5. Follow the usual steps to install the OS. It did not prompt about power connection.
  • Wow interesting that this works. Glad you got it solved. – Thomas Nelson Jul 29 at 23:41

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