If the Ethernet connection on your Mac stopped working recently

If the Ethernet connection on your Mac stopped working recently, you can follow these steps to restore it. 

If the Ethernet connection on your Mac stopped working recently, check System Information to find out which version of “Incompatible Kernel Extension Configuration Data” is installed. If you have version 3.28.1, you need an update. If you can connect to WiFi, your Mac will update to version 3.28.2 automatically, or you can follow the steps below to restore it manually.

First, check your version number

  1. While pressing the Option key, choose System Information from the Apple menu.
  2. Expand the Software section and select Installations.
  3. Click the Software Name column header to sort the list alphabetically.
  4. Look for “Incompatible Kernel Extension Configuration Data.” If the most recent version installed is 3.28.1, follow the steps below.

If you can connect to Wi-Fi, follow these steps to update to version 3.28.2

  1. Open Activity Monitor, which is in the Utilities folder of your Applications folder.
  2. Select the CPU tab in Activity Monitor, then type "updated" in the search field. The softwareupdated process should now be the only item listed.
  3. Open the Terminal app, which is also in your Utilities folder.
  4. Enter this command in Terminal to update to the current version of the “Incompatible Kernel Extension Configuration Data” kernel extension:

    sudo softwareupdate --background

  5. Enter the admin password of your OS X user account when prompted.
  6. Switch back to Activity Monitor. When the CPU usage (% CPU) of the softwareupdated process returns to zero, the kernel extension should be up to date.
  7. Choose Restart from the Apple menu to restart your Mac.

If you can't connect to Wi-Fi, follow these steps to update to version 3.28.2

  1. Restart from OS X Recovery by holding down Command-R while your Mac starts up.
  2. Select Disk Utility from the list of OS X Utilities.
  3. Select your drive from the list of internal drives in the sidebar. The default name is “Macintosh HD.” Your drive might have a different name or location, if you renamed or moved it.
  4. If the drive name is dimmed, it might be protected by FileVault. Choose File > Unlock from the Disk Utility menu, then enter your FileVault password. 
  5. Choose File > Mount in Disk Utility to mount your drive, if it's not already mounted. 
  6. Quit Disk Utility. 
  7. To make it easier to enter the command shown in step 9, you might want to copy it from Safari:
    • Choose Get Help Online from the OS X Utilities list, then go to support.apple.com/kb/HT205956.
    • Select the command in step 9, copy it, then quit Safari before you continue to the next step. 
  8. Choose Utilities > Terminal to open the Terminal app.
  9. Type or paste the following command as one line in Terminal, then press Return. Replace Macintosh HD with the name of your hard drive, if different: 
rm -rf "/Volumes/Macintosh HD/System/Library/Extensions/AppleKextExcludeList.kext"

Now complete these steps to update to the current version of the “Incompatible Kernel Extension Configuration Data” kernel extension:

  1. Quit Terminal.
  2. Choose Restart from the Apple menu. After your Mac restarts, your Ethernet connection should work. 
  3. Open Activity Monitor, which is in the Utilities folder of your Applications folder.
  4. Select the CPU tab in Activity Monitor, then type "updated" in the search field. The softwareupdated process should now be the only item listed.
  5. Open Terminal, which is also in the Utilities folder. Then enter this command:

    sudo softwareupdate --background

  6. Enter the admin password of your OS X user account when prompted.
  7. Switch back to Activity Monitor. When the CPU usage (% CPU) of the softwareupdated process returns to zero, the kernel extension should be up to date.
  8. Choose Restart from the Apple menu to restart your Mac.


Alternatively, if you confirmed that your Mac has Incompatible Kernel Extension Configuration Data version 3.28.1, you can also restart your Mac into OS X Recovery mode, then select Reinstall OS X. You can reinstall OS X on your drive without reformatting it.

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