| mts | Viewpoint MTS Document |
| mud | Autodesk Mudbox Model |
| mug | Hanes T-Shirt Maker Document |
| mup | Music Publisher Score |
| musx | MakeMusic Finale Notation Document |
| mvd | MindView 5 for Mac Document |
| mvdx | MindView for Windows Document |
| mvs | Microchip Verification Specification Data |
| mvtx | MindView for Windows Template |
| mw | MacWrite Text Document |
| Maple Standard Worksheet |
| mw2d | MacWrite II Document |
| mwd | Mariner Write Document |
| mwii | MacWrite II Text Document |
| mwk | Music Write Score Document |
| mwp | Lotus Wordpro Smartmaster File |
| mwpd | MacWrite Pro Document |
| mwpp | MacWrite Pro Document |
| mwpr | MacWrite Pro Document |
| mws | Maple Classic Worksheet |
| mwt | MetaStock Stock Analysis Template |
| mwz | Maple Compressed Worksheet |
| mxs | Maxwell Render Scene |
| mytx | MyThoughts for Mac Document |
| myv | Vivaldi Studio Music Score Document |
| myw | MyWorld Education Drawing Document |
| mz | MOZART Music Document |
| mzt | MOZART Score Template |
| n1e | OM2 OMALI NENA Encrypted Document |
| n2e | OM2 OMALI NENA Encrypted Document |
| n3 | Notation3 Document |
| n3e | OM2 OMALI NENA Encrypted Document |
| n4e | OM2 OMALI NENA Encrypted Document |
| nb | Mathematica Notebook File |
| Nota Bene Document |
| nbk | SMART Notebook Document |
| WaveStar Notebook |
| nbml | Mathematica NotebookML File |
| nbp | Mathematica Player Notebook |
| ncd | Nero Cover Designer Document |
| NoteCase Pro Document |
| nce | NoteCase Pro Encrypted Document |
| nct | Nero Cover Designer Template |
| ncw | Nero Cover Designer Template |
| ncz | Netcad Drawing Document |
| NoteCase Pro Compressed Document |
| nd | Intuit QuickBooks Network Data File |
| ndb | MyDraw Binary Drawing Document |
| ndg | Network Notepad Network Diagram |
| ndo | Nendo Enhanced Native File |
| ndoc | Naver Word Document |
| ndtx | MyDraw XML Drawing Template |
| ndw | Nemetschek Allplan Document |
| ndx | MyDraw XML Drawing Document |
| ne1 | OM2 OMALI NENA Encrypted Document |
| ne2 | OM2 OMALI NENA Encrypted Document |
| ne3 | OM2 OMALI NENA Encrypted Document |
| ne4 | OM2 OMALI NENA Encrypted Document |
| nec | NEC-JIS Encoded File |
| neu | Pro/ENGINEER Neutral Assembly |
| nfd | Nefsis Document |
| nff | WorldToolKit Neutral File Format Data |
| nfo | Microsoft System Information File |
| NFO File |
| nft | NetObjects Fusion Template |
| ng | Norton Guide |
| ngdoc | AngularJS Document |
| ngloss | Nisus Writer Pro Glossary |
| nhb | Nero Burning ROM AVCHD-Video Compilation Data |
| nhf | Nero HFS CD Compilation |
| nhv | Nero HD-Burn Video Compilation |
| njx | NJStar Japanese WP Document |
| nlbl | NiceLabel Label |
| nld | Network Logic Diagram Document |
| nlx | FormWorx Form Document |
| nm5 | NovaMind 5 Mind Map Document |
| nmbtemplate | Numbers Spreadsheet Template |
| nmd | Nero MiniDVD Compilation |
| nmind | NovaMind 4 Mind Map Document |
| nms | Note-Mate Question Set |
