MSWMM - Windows Movie...
File Extension MSWMM
Information about MSWMM files and how to open them
Movie created with Windows Movie Maker; contains the movie timeline, transitions, and references to video clips, audio files, and still images used by the movie. Windows Movie Maker allows the user to combine and edit content saved within an MSWMM file. Once the movie is finished, it can be exported in a standard video format or burned to a DVD.