If you woke up today and your ethernet port is not working, it’s because Apple put out a secret release last night that broke it.  (You didn’t even need to download a software update, it came overnight…)

Apple haven’t released a fix yet but nurds all over the world are trying to solve it.

This seems to be the best fix, but it’s complicated. Print this  out because when you reboot into Recovery Mode you can’t access your files. Once you are in Recovery mode you can choose ‘Browse Apple Help’ and then it will open Safari, then you can come back to macintoshhowto.com and read these instructions. But you will have no Safari Bookmarks.

Confirm you have the problem:

Go to  About This Mac: System Report: Software: Installations

Sort by ‘Install Date’

Look for this:

‘Incompatible Kernel Extension’ 3.28.1  means you have the problem!

Here’s the fix:

1. Download this file https://www.dropbox.com/s/a9ttv4fy7zl2vtf/AppleKextExcludeList.kext.tgz?dl=0

OSX will unpack it then move it to the trash. Copy it from the trash to “Macintosh HD”. (The boot disk on your computer.)

2. Boot into Recovery mode. Do this by rebooting and holding Command+R until the Apple logo appears.

3. Go to the Utilities dropdown in the menu bar, open Terminal and type this: (Assuming your Hard disk is called “Macintosh HD”)

cd /Volumes/Macintosh\ HD

Then type this:

tar -xvzf  AppleKextExcludeList.kext.tgz

type: reboot or select reboot from the menu.

Source:

https://discussions.apple.com/message/29844595#29844595