ethernet port showing link is down when system is in running state

Question

Every ethernet adapter port showing link is down when system is in running state

Answer 1

Hello,

Thank you for posting question on Microsoft Windows Forum.

Based on the issue description, this might indicate a systemic configuration error, a driver conflict, or a power management glitch. Especially when every port simultaneously.

The following are some suggestions that you can try to see if it works.

1.Check Physical Layer.

• Try plugging the same cable into another device to confirm link lights come on.

2.Reset The Power Cycle.

• Sometimes the Ethernet controller gets stuck in a "deep sleep" state that a simple reboot might not fix. Try to shut down the computer completely (hold Shift while clicking Shut down in Windows to force a full shutdown) or unplug the power cable from the PC (if it is a wall socket). Hold the power button on the case for 30 seconds. This will drain residual electricity from the motherboard capacitors. Then plug the power back in and boot up. Check if the link lights on the port are now active.

3.Disable "Green Ethernet" and Power Saving.

• Windows sometimes turns off network cards to save power, erroneously thinking they are idle. Right-click the Start button and select Device Manager. Expand Network adapters. Right-click your Ethernet Controller and select Properties. Tab 1: Power Management: Uncheck "Allow the computer to turn off this device to save power." Tab 2: Advanced: Look for settings named Energy Efficient Ethernet, Green Ethernet, or Power Saving Mode and set them to Disabled.

4.Force Link Speed.

• Auto-negotiation between your PC and the router/switch might be failing. Go back to Device Manager > Network Adapter > Properties > Advanced. Find Speed & Duplex. Change it from "Auto Negotiation" to 100 Mbps Full Duplex (Just for testing). If this works, your cable might be damaged (unable to handle 1Gbps) or the switch port is faulty.

5.Driver/Firmware Incompatibility After Update.

• Roll back to previous driver/firmware if problem started after update.

Hope the above information is helpful! If it is. Free feel to hit "Accepted" for benefitting others in community having the same issue too.