After performing a clean Windows 11 Home installation, my wired Ethernet connection works for a few minutes after restarting, then disconnects and Windows switches to Wi‑Fi. Sometimes the Wi‑Fi connection also stops working. I've already tried reinstalling the Ethernet driver, using Windows Update's repair/reinstall option, downloading drivers from the motherboard manufacturer, testing another Ethernet cable, and running several Command Prompt network commands. The driver download does not appear to launch an installer. My system uses an ASUS ROG Strix B550-I Gaming motherboard, Windows 11 version 25H2, OS build 26200.8973. What else should I check?
2 Answers
Try disabling the Wi‑Fi adapter in Device Manager or in the system firmware, then reboot and see whether Ethernet stays connected. If the wired connection works afterward, Windows may be dealing with an adapter or driver conflict. Also check that the Ethernet adapter is actually enabled in Device Manager.
That motherboard uses an Intel I225 2.5Gb Ethernet controller, which is known to drop its connection under certain auto-negotiation and power-saving settings. In Device Manager, open the adapter’s Properties and go to Advanced. Disable Energy Efficient Ethernet, then set Speed & Duplex to 1.0 Gbps Full Duplex instead of Auto Negotiation. The fixed speed setting is often the change that makes the connection stable.
The manufacturer download may not include a normal installer. Extract the files, choose Update driver in Device Manager, and point it to the extracted folder so Windows can locate the appropriate .inf file.
Enabling the adapter in Device Manager fixed the immediate problem. I also changed the recommended Ethernet settings, and it’s helpful to know that the downloaded driver package needs to be selected manually rather than launched like a typical installer.
Disabling Wi‑Fi made the system show the disconnected-network icon, but I eventually found that the Ethernet adapter itself had been disabled in Device Manager. Enabling it brought the connection back.