That happened to me several times before I realised that maple story comes with the maximum Hertz tax avalaible to your monitor, and that kept the game crashing to me.
Open Maple Story folder, run setup.exe, and it will show several Resolutions x Hertz options, even if you see the window, dont click on "I See the window", wait for the Resolution x Hertz is the same one that your monitor is adjusted to.
