Based on community testing and recent wiki updates, here are the top-performing and most problematic drives:
If you are using an older mechanical HDD and it isn't spinning up, you likely need a USB Y-Cable to draw power from both Wii USB ports. To give you the best setup advice, let me know: Do you already own a specific drive you're trying to use? Are you planning to play GameCube games as well? Are you on an original Wii or a Wii U (vWii) ? usb loader gx usb compatibility list exclusive
Modern drives can work if you use a (two USB-A male ends into one micro-B). One end goes into USB port 0 (bottom), the other into USB port 1 (top). This doubles the power budget to 1000mA. Based on community testing and recent wiki updates,
(the one closest to the edge/bottom when horizontal) unless you have specific cIOS (like d2x v9+) installed. Power Issues Are you on an original Wii or a Wii U (vWii)