Unidentified network on Ethernet, explained and fixed
Windows shows “Unidentified network” on a wired Ethernet connection when it cannot identify the network it is plugged into. The usual cause is a failure to get an IP address from the router, but a bad cable or a wrong IP setting can produce the same message.
The fix, in order
Check the cable. Unplug the Ethernet cable at both ends and plug it back in firmly. Try a different cable and a different port on the router, and check that the port lights are on.
Release and renew the IP address. Open Command Prompt as administrator and run ipconfig /release then ipconfig /renew.
Reset the network stack. In the same admin Command Prompt, run netsh winsock reset and netsh int ip reset, then restart.
Set the IP address to automatic. In the adapter properties, open Internet Protocol Version 4 (TCP/IPv4) and make sure both “Obtain an IP address automatically” and “Obtain DNS server address automatically” are selected.
Disable and re-enable the adapter. Press Windows key plus R, type ncpa.cpl, right-click the Ethernet adapter, choose Disable, wait a few seconds, then choose Enable.
Update the Ethernet driver. In Device Manager, update the driver for the Ethernet adapter, or install the latest one from the computer maker's support site.
If the PC gets a 169.254 address, Windows gave itself a fallback address because DHCP failed. That confirms the router is not handing out addresses, so focus on the router and the cable, not on browser settings.
If it still happens
If the message appears on every wired device, the router's DHCP service or its Ethernet ports are at fault, so restart the router and check its settings. If only one PC is affected, try a different cable and port first, then reinstall the Ethernet driver.
Common questions
What does “Unidentified network” mean? It means Windows is connected to something by cable but cannot identify the network, usually because it did not receive a valid IP address from the router.
Can a bad Ethernet cable cause “Unidentified network”? Yes. A damaged cable can link up just enough to be detected but not well enough to carry DHCP traffic, so the PC never gets an address.