There are 2 file types use the .MIO file extension:
1. WarioWare D.I.Y. Microgame File
A MIO file is a game data file used by WarioWare D.I.Y., also known as Made in Ore (MIO) in Japan, a Nintendo DS game used to design microgames that can be played by other gamers. It is stored in WarioWare D.I.Y. .SAV files and contains a microgame, which may also include game records or comics.
Microgames, also known as mini games, are simple and short games that can be played in WarioWare video games. These games are typically less than 5 seconds.
MIO files can be extracted from WarioWare SAV files using miotool, which can also be used to import MIO files back into SAV files. MIO files make it easier for gamers to share microgames with other WarioWare gamers and also take up less space.
Updated: August 20, 2018
2. MioEngine Application File
Application file built by MioFactory, software package used to develop applications for the free MioEngine platform; stores all application files in a single archive that can run independently in MioEngine; commonly used to build widgets, screen savers, and other Windows applications.
MIO files contain executable code and application resources such as images, video, audio, and other data files. They also contain an XML configuration file, which allows users to update settings without rebuilding the application.
When MioFactory builds a MIO file, it creates a file named identity.kexe that contains the program code for the application. This file is written in MioScript, a scripting language that is interpreted by MioEngine.
NOTE: In order to run MIO files, you must rename mioEngine.exe (the MioEngine platform executable) to the same filename prefix as the target MIO file. For example, "myWidget.mio" can be run when "mioEngine.exe" is renamed to "myWidget.exe".
Updated: January 10, 2010