If your Mac model still supports Ethernet, Apple may have accidentally updated your computer to today’s standards: On some Macs, the last time you update to OS X, the network port stops working. Of course, sometimes this requires a full-fledged hardware repair of the iMac, but often you can try to fix the problem yourself. After one of the updates, many users suddenly found that their poppies could no longer connect to the network, and the Ethernet connector did not work. Therefore many messages appeared on the Internet with complaints. At this point, Apple has officially acknowledged the problem, as evidenced by the corresponding recommendations on the support page. Fortunately, this software error is not irreversible and can be fixed in most cases without any problems.
Apple has already fixed this bug in the latest build of OS X. However, if you received the update earlier, use the method below to resolve it.
If the network port on your computer has stopped working, first you need to find out the number of the latest update “Incompatible Kernel Extension Configuration.” If the file number is 3.28.1, you will need to update it to the latest version to get the Ethernet connector back working. Apple accidentally blocked its network driver, which caused the problem.
To find out the version of the “Incompatible Kernel Extension Configuration” file, hold down the Option key and click on the Apple icon in the top menu. In the window that appears, the item “System information …” will appear. Next, you need to select the “Software” section and find the “Settings” line there. If the latest “Incompatible Kernel Extension Configuration” file is 3.28.1, you will need to update the settings configuration.
If you have access to wireless networks, getting the Ethernet connector back on track is easy enough. To do this, open a terminal and execute the command below and enter the password.
You will need to restart your computer to apply the changes. Once turned on, the Ethernet port should work again. If, for some reason, you are unable to use Wi-Fi, the solution will be a little more complicated. You will need to shut down your Mac and boot into recovery mode, then manually delete the problematic file using Disk Utility and Terminal. To do this, select the required volume and run the following command:
Full instructions on how to fix the problem are described on the Apple support page. Despite this thesis’s obviousness, we remind you that it is highly undesirable to delete anything other than the file you are looking for because this can create problems in the system that are much more serious than the one we are trying to solve. Another solution to the problem is to use recovery mode to reinstall OS X. This is a much simpler solution to the problem; however, the downside of this approach is the loss of user data. Make sure you back up all important files just in case.