Saving a project
Saving your project lets you keep your current work, and then later open the file in Windows Movie Maker to make further changes. You can continue editing your project from where you left off when you last saved the project. When you save a project, the arrangement of clips added to the storyboard/timeline, as well as any video transitions, video effects, titles, credits, and any other edits you made are retained.
A Windows Movie Maker is saved with a .mswmm file name extension.
You can also save an existing Windows Movie Maker project file with a new name. This enables you to use the saved project as the basis for other new projects. For example, if your current project contains a short introduction to a movie, you can save the existing project with a new name and then continue editing. When you wanted to create a new movie that includes the same short introduction, you can then open the original project file that contains only the introduction, and then make additional edits without needing to re-create the introduction of your movie.