| mm3d | Misfit Model 3D Model |
| mm6 | Money Manager 6 Data |
| mmads | MMADS Chemical Modeller Input Data |
| mman | Emailer MMAN Data |
| mmap | MindManager Map File |
| mmas | MindManager Theme |
| mmat | MindManager Map Template |
| mmb | Mobile Master Backup |
| mmc | Microsoft ClipArt Gallery Catalog |
| mmcif | mmCIF Data |
| mmcollection | Mail Manager Collection Data |
| mmd | MacroModel Molecular Mechanics Data |
| mmd | mAirList Metadata |
| mmd | Mangodata Database |
| mmd | Media Processing Server Audio Data |
| mmd0 | Foobar2000 Data |
| mmdb | MaxMind GeoIP2 Database |
| mmdb | Molecular Modeling Database |
| mmdl | Sapphire Structure Model Data |
| mmdr | Adobe Director MMDR Data |
| mme | MIME Encoded Data |
| mmes | Mastersizer 3000 Data |
| mmf | Microsoft Mail Message Format Data |
| mmi | Media Processing Server Index File |
| mmjb | Musicmatch Jukebox Data |
| mmjb_mime | Musicmatch Jukebox MIME Data |
| mmjs | Adobe Dreamweaver Javascript |
| mml | Media Catalog MML File |
| mmlic | Mobile Master License Data |
| mmmacro | Mini Mouse Macro Data |
| mmmp | MindManager Map Part |
| mmms | MindManager Map Marker List |
| mmn | Memory-Map Navigator Data |
| mmo | Memory-Map Overlay File |
| mmod | MacroModel Molecular Mechanics Data |
