LightAtom

Mac Ethernet Not Working: Fixes

Your Mac doesn't get a connection over Ethernet: no link, no address, or Wi-Fi keeps taking priority. Work from the cable inward.

You plugged in an Ethernet cable but your Mac shows it as not connected, gets no IP address, or keeps using Wi-Fi instead.

  • System Settings › Network shows the Ethernet service as Not Connected or with a self-assigned IP.
  • The adapter's link lights are off.
  • Traffic still goes over Wi-Fi.

Quick fix

Unplug and replug the cable and adapter, then check System Settings › Network. The Ethernet service (often named after the adapter, such as “USB 10/100/1000 LAN”) should show a green dot and an IP address. If it shows Not Connected, swap the cable or the router port.

Why it happens

Faulty cable, adapter or router port.Most likely
USB-C or Thunderbolt adapter not recognised or under-powered (via a hub).Sometimes
Wi-Fi is higher in the service order.Sometimes
DHCP didn't hand out an address.Sometimes
Manual IP or VLAN settings from another network.Rarely

Fixes

  1. Check the physical link

    1. Look for link lights on the adapter and router port; try another cable and port.
    2. Plug the adapter straight into the Mac rather than through a hub.
    3. In Terminal, ifconfig | grep -B6 'status: active' lists interfaces with a link.

  2. Check the service in Network settings

    1. If the adapter isn't listed, click ⋯ › Add Service and choose it.
    2. Details › TCP/IP: Configure IPv4 Using DHCP, then Renew DHCP Lease.

  3. Prefer Ethernet over Wi-Fi

    1. System Settings › Network › ⋯ › Set Service Order: drag the Ethernet adapter above Wi-Fi.

  4. Check speed and duplex

    1. Details › Hardware: keep Configure set to Automatically; manual speed settings can prevent a link.

Still not working?

If no cable or port gives a link, try the adapter on another computer. Cheap adapters sometimes need a driver or simply fail; a known-good adapter settles it quickly.

See it in the app

LightAtom's connections view keeps working across interfaces, so you can see apps reconnect when the Mac switches from Wi-Fi to Ethernet.

Frequently asked questions

Why does my Mac use Wi-Fi when Ethernet is plugged in?

The service order decides. Put Ethernet above Wi-Fi in System Settings › Network › ⋯ › Set Service Order.

Do Macs need drivers for USB Ethernet adapters?

Most common adapters work without drivers on current macOS. Some older or unusual chipsets need a vendor driver; check the adapter maker's site.

Is Ethernet faster than Wi-Fi on a Mac?

It's usually more stable with lower latency and jitter. Raw speed depends on the adapter (1 Gbps or more) versus your Wi-Fi conditions.

Related

LightAtom team

The people who build LightAtom, a network monitor for macOS.