Ethernet won't work after fresh Win11 OS install... Not the usual suspects

I moved my PC from one room to the next, and somehow broke Windows. PC starts up just fine, but turns off the second Windows 11 starts to boot.

Everything, including disk access, was just fine… I gave up on it and reinstalled Windows 11.

Now the ethernet port on the motherboard is not working (no lights when ethernet is plugged in, no network/internet on Windows), and I am stumped.

  • Ethernet cable is good. It works when I connect to the PC over a USB Ethernet adapter, or to other devices.
  • The motherboard ethernet adapter shows up in device manager.
  • DHCP and other usual network settings were enabled.
  • I tried Asus’s driver (ASUS ROG Strix Z690-A) as well as the default Windows/Microsoft one.
  • I tried older versions of Asus’s driver.
  • Disabling/Enabling or removing and checking for hardware changes in device manager didn’t fix it.
  • Windows connects to the network/internet using the onboard Wi-Fi or a USB ethernet adapter.
  • Green flashing activity light turns on when I disable the motherboard ethernet port in device manager.
  • Green flashing light is also on during boot or in BIOS, but it turns off when Windows starts.
  • Intel LAN is enabled in the BIOS.
  • Restarting or resetting the BIOS didn’t help.

The ethernet port worked fine yesterday and has been working perfectly for the last two years. I’ve never needed to install a driver for it on Windows 10 or 11.

Any ideas?

EDIT -----------------------------

I gave up and installed a PCI-E 2.5GB Ethernet adapter from Trendnet. It worked perfectly on the first startup. I still have no idea why Windows suddenly started to hate the onboard ethernet port I’ve been using without any issue for years.

Making changes to your system BIOS settings or disk setup can cause you to lose data. Always test your data backups before making changes to your PC.

For more information, please see our FAQ thread: https://www.reddit.com/r/techsupport/comments/q2rns5/windows_11_faq_read_this_first/

Is it picking up an IP address at all? You should see an ethernet adapter in the list with an IPv4 address when running the following command: ipconfig /all

If you’re getting a 169.x.x.x address, double-check that no static IP is assigned and that DHCP is enabled.

@Flynt
There was no IP for that port, as Windows was disabling it and acting like the cable was disconnected:

>Ethernet adapter Ethernet:

> Media State . . . . . . . . . . . : Media disconnected

> Connection-specific DNS Suffix . :

> Description . . . . . . . . . . . : Intel(R) Ethernet Controller (3) I225-V

> Physical Address. . . . . . . . . : 50-2B-F6-CC-D9-24 (I changed this -GOR)

> DHCP Enabled. . . . . . . . . . . : Yes

> Autoconfiguration Enabled . . . . : Yes

DHCP was enabled. But Windows recognized and adopted the PCI-E ethernet adapter I just plugged in with no issue.

@Chase
Ahh, did it allow you to switch it to enabled in the control panel?

Flynt said:
@Chase
Ahh, did it allow you to switch it to enabled in the control panel?

Switch what? The DHCP vs manual setting?

Yes.

Super weird, right?

Chase said:

Flynt said:
@Chase
Ahh, did it allow you to switch it to enabled in the control panel?

Switch what? The DHCP vs manual setting?

Yes.

Super weird, right?

Sorry, I think I misunderstood earlier. I realize now that it wouldn’t have shown in ipconfig if it was disabled in the control panel.

This issue is strange. If your other NICs weren’t working, I’d be suggesting trying a new cable, haha.

Anything showing on the ‘Events’ tab under the device manager properties?

At least you got something running with the new adapter!