Get your Mac's Ethernet cable or adapter working again

Why it happens

A wired connection fails for three main reasons: the cable or adapter isn't making contact, the Mac doesn't see the adapter, or the router hasn't given the Mac an address. Network settings tells you which one it is. A green dot and Connected means the link is fine and the problem is the address or the router.

How to fix it

1. Push the cable firmly into both the Mac (or adapter) and the router until it clicks. Look for lights next to the router's port. If there are none, try another cable or another port on the router.

2. Using a USB-C, Thunderbolt or USB adapter? Plug it straight into the Mac, not through a hub. If your Mac asks whether to allow the accessory to connect, click Allow.

3. Open Network and find your wired connection. It may be called Ethernet, or named after your adapter, like USB 10/100/1000 LAN or Thunderbolt Ethernet. A green dot and Connected means the link is working.

   Network›Ethernet

4. Click it, then click Details…, choose TCP/IP and click Renew DHCP Lease. Click OK and give it a few seconds.

Ethernet settings are the same on macOS 26 and 27. Only Allow accessories to connect moved: it's under Security on 26 and under Accessories on 27.

Still not fixed?

1. If your Mac never asked, check Allow accessories to connect. On macOS 26 it's under Security in Privacy & Security; on macOS 27 it's under Accessories.

   macOS 26 Tahoe Privacy & Security›Security›Allow accessories to connect

   macOS 27 Golden Gate Privacy & Security›Accessories›Allow accessories to connect

2. Connected but still no internet, with Wi-Fi also on? Put Ethernet above Wi-Fi: click the three-dot button at the bottom of the Network list and choose Set Service Order….

   Network›⋯ (action menu)›Set Service Order…

3. Restart the router or modem by unplugging it for 30 seconds, then restart your Mac.

4. If the adapter never shows up in Network settings, try it on another Mac. If it fails there too, the adapter is faulty and needs replacing.

5. If your Mac's own Ethernet port, on an iMac, Mac mini or Mac Studio, never detects any cable, that's hardware. Contact Apple Support or a repair shop.