My mouse isn't recognized by the PC. The message says "Unknown USB-Device".

a. Please reinstall the mouse driver (windows device manager) and try again.
b. Test the unit on another PC and/or another USB-port.
c. Please try to remove mouse driver software of other brands if any are installed, as to avoid driver conflicts to windows USB driver.

If the problem persists, please contact us (ZOWIE website/Support/Contact/RMA).