| mlw | MainLog Data |
| mlx | Meshlab Filter Script |
| mlz | MLZ Data |
| mm | Matrix Market File |
| mm | FreeMind MindMap |
| mm3 | Mortgage Minder v3 Data File |
| mm3d | Misfit Model 3D Model |
| mmap | MindManager Map File |
| mmas | MindManager Theme |
| mmat | MindManager Map Template |
| mmb | Mobile Master Backup |
| mmc | Microsoft ClipArt Gallery Catalog |
| mmd | Media Processing Server Audio Data |
| mmd | mAirList Metadata |
| mmdb | Molecular Modeling Database |
| mmdb | MaxMind GeoIP2 Database |
| mme | MIME Encoded Data |
| mmi | Media Processing Server Index File |
| mmjb | MusicMatch Jukebox Data |
| mml | Media Catalog MML File |
| mmmp | MindManager Map Part |
| mmms | MindManager Map Marker List |
| mmo | Memory-Map Overlay File |
| mmr | Sybase PowerDesigner Multimodel Report |
| mmt | Nimbus 7 SAMS MMRVT Data |
| mmu | myPM Merge Data |
| mmw | Microsoft Office Clip Organizer Catalog |
| mmysyscache | Milennial Media Ad Cache |
| mn8 | Microsoft Money 8 Data |
| mnc | Autodesk AutoCAD Compiled Menu |
| mnd | Fractal Forge v2 Fractal Parameters |
| mnf | MSC Adams Model Neutral Data |
| mni | Cerious Mandelbrot Image |
| mnk | My Notes Keeper Notebook |
| mnm | Autodesk Character Studio Marker Name |
