Every time I start my PC, the motherboard displays: "Over Current Have Been Detected On Your USB Device!! System will shutdown after 15 seconds to protect your mainboard!!" I disconnected every external USB device and cable, then opened the case and unplugged all internal USB headers, but the warning still appears. Before this started, Windows repeatedly showed "Power surge on the USB port," and now the system shuts down before Windows can load. The motherboard is an MSI B550 Tomahawk Max WiFi purchased about a month ago. What could still be causing the short, and what should I check before considering a motherboard replacement?
4 Answers
If the board has an M.2 Wi-Fi card installed, remove it temporarily too. Bluetooth on some Wi-Fi modules uses an internal USB connection, so it can still be part of the USB bus even after the case headers are disconnected.
Check every USB port on the motherboard and case carefully for bent contacts, debris, or a damaged plastic tongue. A bent pin touching the shell or another contact can trigger this warning even when nothing is plugged in. Also inspect the front-panel ports for signs of a spill or something lodged inside.
Since the problem began with repeated power-surge warnings and the board is relatively new, a motherboard fault is possible. After checking for bent or contaminated ports and testing with all USB-related devices removed, contact the manufacturer or seller for warranty service rather than continuing to power-cycle it.
Try entering the BIOS and disabling USB support as a diagnostic step, if the firmware provides that option. If the warning continues with all external devices, front-panel headers, and the Wi-Fi card disconnected, the USB controller or another component on the motherboard may have failed or shorted.
I hadn't considered the Wi-Fi card's Bluetooth connection. I'll remove it and test again.