When you start up maplestory it says input not supported?

The "Input Not Supported" message in MapleStory usually indicates that the game's resolution settings are incompatible with your monitor's display settings. You can try starting the game in windowed mode by adjusting the settings in the game's configuration file, or by pressing specific keys (like Alt + Enter) during launch. Additionally, ensure your graphics drivers are up to date and that your monitor's resolution settings match those of the game. If the issue persists, consider checking forums or support channels for specific troubleshooting steps.