When a USB device isn’t detected, start by testing it in a different USB port. If the device works in another port, the original port may be faulty. Go to Device Manager to check if there’s an error with the USB driver and attempt to update or reinstall it. For powered devices, like external hard drives, ensure they’re plugged into a power source. Additionally, try the device on another computer to rule out device-specific problems. If the issue remains, updating your computer’s chipset drivers can sometimes solve port recognition issues. In cases where none of these steps help, the device might be defective and could require replacement.