Mac OS X showed that a new update was available on my MacBook Air (2019) which I connect to the internet with using a USB-C to ethernet connector. [ I don't use wi-fi at all for health reasons.] After installing the update, my Mac no longer recognises the ethernet connection - the connection does not show up on the switch. I purchased a new USB-C to ethernet adaptor, and it too does not work ... from which I have figured out that the problem appears to be Apple's update. I am running Mac OS Mojave 10.14.6.
Any suggestions as to how to get my MacBook Air running again with ethernet ... is it possible to just install a new (or old or backup version of) the ethernet driver? If so, does anyone know which file to switch. Many thanks