WLMP File Documentation

Summary

A .wlmp file is a Windows Live Movie Maker Project: a small XML text file that records your editing decisions, not a video. It stores the timeline, trims, transitions and titles as a list of references (full file paths) to the source clips, photos and music on your PC. Its MIME type is application/xml. Only Windows Movie Maker opens it; to get a playable video you open the project and use “Save movie” to export an MP4 or WMV.

Technical details

Feature	Value
Full name	Windows Live Movie Maker Project
File extension	`.wlmp`
MIME type	`application/xml`
Format type	XML project file (edit list, references source media)
Contains video?	No — it stores paths to clips, not the footage
Developer	Microsoft
Introduced	2009 (Windows Live Movie Maker, Windows Live Essentials)
Encoding	Plain-text UTF-8 XML
Container / base format	XML
Magic number	`3C 3F 78 6D 6C` (`<?xml` declaration)
Open standard	No (proprietary project schema)
Created by	Windows (Live) Movie Maker — discontinued 10 January 2017
Opens in	Windows Movie Maker only; a text editor to read the paths
Export targets	`.mp4`, `.wmv` (via “Save movie”)
Predecessor format	`.mswmm` (older Windows Movie Maker project)
Related extensions	`.mswmm`, `.wmv`, `.mp4`, `.wp3`

Structure at a glance

A .wlmp is plain-text XML beginning with the <?xml version="1.0" ... ?> prolog, followed by a Movie Maker project root element. Inside, a media list holds the full <path> of every source clip, photo and audio file on disk, and the timeline elements reference those items with in/out trim points, durations, transitions, titles and effects. Open it in Notepad to read exactly which files the project depends on. No coded video or audio is stored, so the file is usually only a few kilobytes.

What is a WLMP file?

A WLMP file is the project format of Windows Live Movie Maker, the free video editor Microsoft shipped from 2009 as part of Windows Live Essentials (later renamed simply Windows Movie Maker). The extension stands for “Windows Live Movie Maker Project”. The single fact that trips up almost everyone who has one: a .wlmp is not a video. It contains no picture and no sound. It is a small XML text file that records your editing decisions and points at the original media files sitting elsewhere on your hard drive.

Open a .wlmp in Notepad and you can read the whole thing. It begins with the XML declaration and holds a list of the clips, photos and music on your timeline, their order and trim points, plus the transitions, titles and effects you applied. What it stores for each piece of media is a file path, not the media itself. That design keeps the project tiny (a few kilobytes) but means the project is worthless without the source files it references.

Plain-text XML, not encoded media

Unlike a real video container such as MP4 or MKV, which stores coded frames and audio samples inside a binary box structure, a .wlmp stores no bitstream at all. It is UTF-8 text. The first five bytes are 3C 3F 78 6D 6C, the ASCII characters <?xml, the standard XML prolog. After the prolog comes a Movie Maker project root element carrying the program version and project settings, then the timeline description.

Because the format is human-readable, you can inspect a project without any special tool. The following is the shape of what you see, simplified:

<?xml version="1.0" encoding="utf-16"?>
<Project version="...">
  <!-- references to source files on disk -->
  <MediaItem id="1" filePath="C:\Users\me\Videos\clip1.mp4" />
  <MediaItem id="2" filePath="C:\Users\me\Pictures\photo.jpg" />
  <MediaItem id="3" filePath="C:\Users\me\Music\track.mp3" />
  <!-- the timeline: which items play, trimmed how, in what order -->
  <Extent mediaItemID="1" inTime="0.0" outTime="6.5" />
  <Transition type="crossfade" duration="1.0" />
  <Extent mediaItemID="2" inTime="0.0" outTime="4.0" />
  <!-- titles, effects, audio levels ... -->
</Project>

The exact element and attribute names are Microsoft’s own and were never published as a public specification, so the layout above is illustrative rather than a schema you should rely on. The point that matters is structural: every clip on the timeline is a pointer to an external file, and the edit is a list of trims and effects layered over those pointers.

Why the project breaks when media moves

Since a .wlmp stores file paths and not the footage, the project only rebuilds correctly on the machine that still has every referenced file in its original location. Copy the .wlmp by itself to another PC and Movie Maker reports the media as missing, because the actual clips were never inside the project. Move, rename or delete a source clip on the same PC and the same thing happens: the pointer no longer resolves.

This is the same “offline media” problem that professional editors hit with MOV-based workflows and other reference-only project formats. The fix is always to restore the referenced files to the paths the project expects, or to relink them where the editor allows it. Movie Maker’s relinking was limited, so keeping the source media beside the project, in the same folders, is the reliable approach.

Save movie: turning the project into an actual file

To produce something you can upload or send, you export, and export is a render, not a file conversion. With the original media present, you open the project in Windows Movie Maker and choose “Save movie”. Movie Maker then reads every referenced clip, applies your trims, transitions and effects, and encodes a new video: an MP4 (H.264) or a WMV, which was Movie Maker’s native output. That output is a real, self-contained video; the .wlmp remains a separate editing file.

There is no .wlmp-to-MP4 converter, and any site advertising one is misunderstanding the format or worse. Nothing can turn the project into a video without the referenced media and an editor to do the encoding, because the pixels simply are not in the file. If you hold only a .wlmp and have lost the source clips, the video cannot be reconstructed.

The software problem: Movie Maker’s end of life

Microsoft discontinued Windows Movie Maker on 10 January 2017 and pulled the official download. Video editing later moved into the Windows 10 Photos app and then into Clipchamp on Windows 11. None of those successors reads the old .wlmp project format, so a project made years ago can only be reopened in a genuine copy of Movie Maker. That gap created a wave of fake “Windows Movie Maker” download sites after the end of life, many bundling adware or charging for the formerly free program; some impersonated Microsoft directly. If you need Movie Maker to reopen a .wlmp, use a copy you already trust rather than a search-ad “free download” portal.

Note also the earlier lineage: the pre-Live Windows Movie Maker (the Windows XP and Vista era) saved projects as .mswmm, a separate and also-defunct format. A modern Movie Maker does not save backward to .mswmm, and neither project format contains a video regardless.

Frequently asked questions

Why won’t my WLMP file play as a video?

Because it is not a video. It is a Movie Maker project: an XML list of edits that points to your original clips. To get a playable file you open it in Movie Maker and use “Save movie” to export an MP4 or WMV.

Why does Movie Maker say my media is missing?

The project stores only paths to the source files. If those clips were moved, renamed, deleted, or the .wlmp was copied to another PC without them, the paths no longer resolve and Movie Maker cannot rebuild the timeline.

Can I see what a WLMP references without Movie Maker?

Yes. Open it in a text editor. Because it is plain XML, the full file paths of every clip, photo and music track are readable, which is useful for locating the media even if you cannot render the project.

References

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