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I installed macOS Sierra 10.12.6 Update

I installed macOS Sierra 10.12.6 Update and as soon as the restart completed my kernel_task is on 270% CPU usage, my fan sounds like a helicopter and my computer barely moves. Please help.

Reboot in Safe Mode, followed by a normal reboot: Use safe mode to isolate issues with your Mac - Apple Support

Have you tried restarting?

Have you tried SMC reset?

Reset the System Management Controller (SMC) on your Mac - Apple Support

I tried this but it didn't help unfortunately,  the issue doesn't seem to be with a 3rd party app

I have tried restarting, rebooting in safe mode, resetting the SMC, downloading the 10.12.6 combo and installing it... nothing seems to work. kernel_task is still on 260% CPU usage and the fan is on overdrive although components not heated at all.

Can I uninstall update or revert somehow to before installing this update?

You can revert if you have a Time Machine backup:

macOS Sierra: Revert to a previous macOS version

If no TM backup, then you need to erase the hard drive and re-install Sierra from the Internet:

macOS Sierra: Reinstall macOS

This will give you the Mac OS your Mac originally shipped with and from there you'll need to upgrade. But the version of Sierra available will be the latest, unless you have a saved installer. Your other choice would be to go with El Capitan.

get El Capitan from the App Store

Mine did that too after 1st failed install attempt.

Fan went nuts and the Magsafe power adapter broke.

MBP wouldn't even recognize it was plugged in (meaning it wouldn't let me reinstall macOS from Recovery).

SMC reset seemed to fix the fan and the charging problem ...

(simultaneously press & then release Ctrl+Shift+Option+Power buttons).

I followed that with PRAM/NVRAM reset (press power and then hold down Cmd+Option+"P"+"R" until 2nd restart chime). That didn't seem to do anything, but if SMC reset alone didn't work for you maybe try that too.

Neither step, nor macOS reinstall fix the failed update though.

The only thing that worked was to restore from a Time Machine backup.

最后更新：2017-08-18 01:09:11

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