Apple: How to Fix Mac Ethernet Ports if they Stopped Working Recently

A recent Apple security update has appeared to have broken ethernet ports for some Mac users, as reported on Reddit and MacRumors. The update seems to disable the ethernet port as one user stated the update “added an exclusion for the stock AppleBCM5701Ethernet driver!”

Apple has now acknowledged the ethernet port issue, and has posted a fix. Here’s how they explain the issue:

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.

So for those with version 3.28.1 of “Incompatible Kernel Extension Configuration Data” installed, you will need to connect to Wi-Fi and manually update to version 3.28.2 automatically—or follow Apple’s instructions on how to restore it manually.

If you can connect to WiFi, follow these steps to update to version 3.28.2:

1. Open the Terminal app.
2. Type this command to update to the current version of the “Incompatible Kernel Extension Configuration Data” kernel extension:

sudo softwareupdate –background

3. Quit Terminal and restart your Mac.

If you can’t connect to WiFi, follow these steps to update to version 3.28.2:

1Follow the instructions to restart your Mac in OS X Recovery. After your Mac restarts, go to step 2.
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 gray, then your drive might be protected by FileVault. Select File > Unlock from the Disk Utility menu, and enter your FileVault password.
5. Select File > Mount in Disk Utility to mount your drive, if it’s not already mounted.
6. Quit 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 before you go to the next step.
7. Launch the Terminal app from Utilities > Terminal.
8. Type (or copy and paste) this command as one line in Terminal. In the example below, the drive name is “Macintosh HD,” and there’s a space between Macintosh and HD. If your Mac’s drive name is different, adjust the text:

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

9. Quit the Terminal app.
10. Select Restart from the Apple menu.
11. After your Mac restarts, your Ethernet connection should work.
12. Open the Terminal app and type this command to update to the current version of the “Incompatible Kernel Extension Configuration Data” kernel extension:

sudo softwareupdate –background

13. Quit Terminal and restart your Mac.

Apple says you can also follow these instructions to restart your Mac into OS X Recovery mode, then select ‘Reinstall OS X’, which will do with without reformatting it.

Let us know if you suffered from this ethernet port issue and if Apple’s fixes solved it.

Founder and Editor-in-Chief of iPhoneinCanada.ca. Follow me on Twitter, and @iPhoneinCanada, and on Google+.

  • I have port issues, but not Ethernet.
    My MacBook Air 2011 has USB issues. They work, but my iPhone disconnect and reconnects if I move the connection a little. I’m not sure if it’s dirty or a wired issue.

  • Mohammed Al Sarraf

    Most likely a cable issue

  • Mohammed Al Sarraf

    Most likely a cable issue
    Change your iphone cable and try it

  • Nope, I’ve tried about 5 different cables, even the one that came with the iPhone. This also did the same thing with my Android cables too. It’s the USB port 100% as these same cables work in other computers and devices without issue.

  • BigCat

    This is very interesting. The following is a quote from the MacRumors forum:

    “This software update was pushed via the silent “security updates” to my iMac today”

    So, there are updates that Apple tells you about and encourages you to apply. But there are also silent updates that happen automatically and do not appear under the updates tab in the App Store?

    Great way to take out or control every Mac that connects to internet.

  • runner

    This is why I always wait a few days to do updates. Glad I missed the hassle – I use ethernet frequently.