| mou | WinMount Archive |
| mozlz4 | Mozilla Firefox Portable Data |
| mpkg | Mac OS X Metapackage |
| mplumpack | Luminar Custom Presets Package |
| mpzip | NI Multisim Package |
| mqxlz | memoQ Compressed XLIFF Archive |
| mrback | Macrium Reflect Backup Data |
| mrbak | Macrium Reflect File and Folder Backup |
| mrex | Macrium Reflect Exchange Backup |
| mrimg | Macrium Reflect Disk Image |
| mrsql | Macrium Reflect SQL Backup |
| msi | Microsoft Windows Installer Package |
| msix | MSIX Package |
| msixbundle | MSIX Bundle Package |
| msm | Microsoft Windows Merge Module |
| msp | Microsoft Windows Installer Patch |
| msu | Microsoft Windows Vista Update Package |
| mtz | Maltego Archive |
| mva | Matrox Setup Program Archive |
| myc | Simply Safe Backup Archive |
| mzf | MediaZip Compressed Archive |
| mzz | Microsoft .NET Download Package |
| n000 | Genie Backup Manager Split Backup Archive |
| nai | WinINSTALL LE NAI Package |
| narc | Nintendo DS Archive |
| nba | Nero BackItUp Backup Archive |
| nbf | NTI Backup Now Archive |
| nbp | ArcSoft Totalmedia Backup Archive |
| nbz | ArcSoft Totalmedia Backup Archive |
| nca | Switch Nintendo Content Archive |
| nfp | Nokia Flash Package |
| nhn | ijji REACTOR Game Package |
| npf | NTI Backup Now Partition File |
| nsarc | Neuro-MEP.NET Software Archive |
| nsk | NaShrinK Compressed Archive |