Recent OS X security update breaks Ethernet for most Macs


One of these ports might not work anymore if you recently installed an OS X update.
One of these ports might not work anymore if you recently installed an OS X update.
Photo: Apple

Did your Mac’s Ethernet port mysteriously stop working recently? If so, you could have fallen afoul of a nasty bug that was introduced in a recent OS X security update. Here’s how to fix it.

As pointed out on Reddit, a recent OS X security update called “031–51913 Incompatible Kernel Extension Configuration Data 3.28.1” blacklists the BCM5701 driver.

The only problem? Almost every Mac with an Ethernet port depends on that driver. And while Apple has since pulled that update from their servers, there’s a chance you might have been afflicted.

Right now, the only way to get your Ethernet port back if you accidentally installed the update is toi boot into OS X Recovery Mode and then restore this folder from a Time Machine or other backup:


Otherwise, wait to see how Apple decides to address this issue. Come next week, they may well issue an official fix. And let’s hope. For millions of people, the Ethernet port’s a pretty indispensable aspect of their computer.

Source: Reddit

  • Andrea T

    I also use the Ethernet port on the iMac, but… “million of people” comes from some data or is just made up?

    • Chris

      Made up, almost certainly. I’d guess less than 5% of people wire their computers on the network. That 5% number, is just made up too, by the way. ;-)

  • Eurocratique

    It hasnt affected my iMac (21,5′, 2013)

  • matt

    someone on reddit said that if you go to terminal and run sudo softwareupdate –background it will restore /System/Library/Extensions/AppleKextExcludeList.kext from apple’s servers

  • jonen

    Blacklisting their own ethernet module…

    • DrMuggg

      Makes u miss Steve even more. The guys behind this would have been fired, on the spot… – Get out, or in 15 min we’ll have security escort you out and throw you into the pavement.

      • Steve

        such a cliché

      • DrMuggg

        Maybe, but I-m sure this misktake would not have shown up if Jobs was in charge.

      • Duncan Hill

        no mistakes were ever made while Jobs was in charge.

      • DrMuggg

        Oh Yes, they made mistakes. But everyone was puttig effort in, really, big time, to avoid them. Beacuse if you made one, you walked out the door forever the same day…