Apple acknowledges OS X security update causes Ethernet connection break on Mac: How to fix

A recent security update released for Mac breaks Ethernet connection, forcing users to opt for some other means of connectivity to get online. The update "031-51913 Incompatible Kernel Extension Configuration Data 3.28.1" adds BCM5701 Ethernet driver and upon the installation of the update, the Ethernet port stop working.

Apple has acknowledged the issue and released a fix, allowing users to restore their connection. If you face the same issue, head over to the System Information on your Mac to find out which version of "Incompatible Kernel Extension Configuration Data" is installed. If it is version 3.28.1, you need to update your Mac to version 3.28.2. Check out the following steps to update the latest version on Mac.

To check the version number of your Mac

• Select System Information from Apple menu, while pressing the Option key
• Click the Software section and select Installations
• Click on the Software Name column header to sort the list alphabetically
• Navigate to "Incompatible Kernel Extension Configuration Data." You should see the most recent version installed is 3.28.1

Do the following steps to update to version 3.28.2

• Open the Terminal app
• Type the following command to update to the current version of the Incompatible Kernel Extension Configuration Data" kernel extension

sudo softwareupdate - - background

• Quit Terminal and restart your Mac

If you cannot connect to Wi-Fi, check out the following steps to update to version 3.28.2

• Restart you Mac in OS X Recovery
• Follow the instructions to restart your Mac in OS X Recovery
• Select Disk Utility from the list of available options in OS X Utilities.
• Select your drive from the list of internal drives in the sidebar. The default name of your drive is Macintosh HD
• If the drive name is gray, then it is protected by FileVault. Select File>> Unlock from the Disk Utility menu then enter your FileVault password
• Select File>> Mount in Disk Utility to mount your drive
• Close Disk Utility. If you'd like to be able to copy and paste the command required in Step 8, select Get Help Online from the OS X Utilities list to open Safari and view this article on Apple's support site at support.apple.com/kb/HT6672. Quit Safari
• Go to Utilities >> Terminal to open the app
• Type the following command in Terminal

rm -rf "/Volumes/Macintosh HD/System/Library/Extensions/AppleKextExcludeList.kext"

The drive name is Macintosh HD in the above command. If your Mac's drive name is different, then adjust accordingly

• Close Terminal app
• Select Restart from the Apple menu
• Once the Mac restarts, your Ethernet connection should work
• Open the Terminal app and type the following command to update to the current version of the "Incompatible Kernel Extension Configuration Data" kernel extension:

sudo softwareupdate --background

• Quit Terminal and restart your Mac

To know more about the Ethernet connection on Mac, head over to Apple support page.