“If you’re reading this and your Ethernet port is working fine, odds are good that you’ve already installed the follow-up update released to fix the problem,” Cunningham reports. “The culprit is an update for System Integrity Protection, the El Capitan feature that protects some system folders and keeps unsigned or incorrectly signed kernel extensions (or ‘kexts,’ roughly analogous to drivers in a Windows or Linux machine) from loading. ”
Cunningham reports, “In this case, the kext used to enable the Ethernet port on Macs was blacklisted—if you restarted your Mac after applying this update but before your computer had a chance to download the quickly issued fix, you’ll find yourself without an Ethernet connection.”
Read more in the full article here.
MacDailyNews Note: Instructions for the fix is here.