Yamaha XGPlayer 4.0.1.52 Update for S-YXG50 version 3.x & version 4.x WDM:

Note - Be sure to close the Yamaha XG Player program before installing the
       updated XG Player files.

Extract all the files from the Yamaha-XGplayer-V40152-Update-SYXG50V3V4.zip file
onto the \Yamaha\SYXG50\ or the \Program Files\Yamaha\SYXG50\ folder.
Overwrite the existing files with the new ones as needed to perform the update.
Then reload the Yamaha XGPlayer program.