Expert advice needed ASAP!: Can't get Ethernet setup with USB adaptor
I'm suddenly seeing a problem where my MacBook is refusing to connect to Ethernet, despite that a known working USB to Ethernet Adaptor (Realtek chip) is connected to the MacBook.
The adaptor I'm using is a standard USB to Gigabit Ethernet adaptor, using a Realtek chip. So no drivers are necessary, and has worked flawlessly in the past.
All of a sudden, it would not detect the Ethernet connection at all, even though the System Information clearly shows that the "USB 10/100/1000 LAN" is connected and working. Even if I connect a cable to the adaptor, it doesn't go online in the Network Preferences panel.
I thought I might need to delete the connection and add it again, only to find that you can't add the USB Ethernet connection in Network Preferences, as shown below.
Note how it is detecting the USB adaptor, but doesn't appear in Network Preferences.
I'm stumped. Any help appreciated!
I've posted a same question on the Big Sur forums, but with no help or reply whatsoever... perhaps the MacBook section may be better thus reposting the same question here.