Even though the driver is correctly installed and the corresponding hardware (for example CMC series, CC121, MR series) is working, the control panels of both the 'Yamaha USB-MIDI Driver' and 'Yamaha Steinberg FW Driver' (FireWire) are missing from the 'Hardware and Sound' category of Windows' Control Panel.
The issue only occurs if the Yamaha Steinberg FW Driver resp. Yamaha USB-MIDI Driver has been installed on a Windows 10 system that has been updated to Windows Fall Creators Update (v1709) later.
Go to Control Panel and set 'View by:' (at the upper right above the control panels) from 'Category' to 'Large icons' or 'Small icons'.
To solve the display issue permanently, please uninstall the Yamaha Steinberg FW Driver and/or Yamaha USB-MIDI Driver properly via 'Apps & features'. Afterwards, restart your system and finally reinstall the latest driver version: