| mwv | MediaWorks Data |
| mx | Mathematica Serialized Package |
| mx2 | MasterCook Recipe Data |
| mxad | Mandelbrot Explorer All Data |
| mxaddon | Maxthon Browser Add-On |
| mxc | ArcVIEW Geocode Coverage ODB Index |
| mxc2 | MAGIX Thumbnail Cache |
| mxcs | Mandelbrot Explorer Color Scheme |
| mxd | ArcMAP Document |
| mxdic | Maxthon Browser Dictionary |
| mxdl | Maxthon Browser Incomplete Download File |
| mxe | Macro Express Playable Macro |
| mxfassoc | Adobe Premiere MXF Association Data |
| mxfd | Abbyy eFormFiller Form File |
| mxfr | Mandelbrot Explorer Fractal Region Data |
| mxfx | NI Maschine Effects Plug-in Presets Data |
| mxg | Miinoto Exchangeable Group |
| mxgrp | NI Maschine Group Data |
| mxinst | NI Maschine Instrument Plug-in Presets Data |
| mxit | MXit Data |
| mxliff | Memsource XLIFF Data |
| mxm | Maxwell Render Material |
| mxml | Mercury Motif Data |
| mxn | MultiNote Exchangeable Notes |
| mxq | SA Chess MXQ Data |
| mxr | MatrixREDUCE 2.0 PSAM XML Format Data |
| mxrw | Mandelbrot Explorer RAW Data |
| mxs | ArcVIEW Geocode ODB Index |
| mxs | Carlson 2016 Multiple Cross Sections Data |
| mxsd | IBM WebSphere Message Definition Data |
| mxskin | Maxthon Browser Skin |
| mxt | Fortran 5 Data File |
| mxz | Maximizer CRM Data |
| my3d | Hasbro My3D File |
| myb | MYOB AccountRight Company Data |
