| mex | Corel WordPerfect ME Expound Data |
| mex | Macro Express Macro File |
| mex | MAXQDA Exchange Data |
| mexp | MetaMorph NX Experiment Data |
| mez | RealArcade Game Information Data |
| mf | Adobe FrameMaker Maker Data |
| mf | Zemax Merit Function Data |
| mf4 | ASAM Measurement Data Format File |
| mfalist | Ashampoo Photo Commander Slideshow List |
| mfasl | Mozilla Fastload File |
| mfc | CMUSphinx Features Data |
| mfcc | HTK Mel-Frequency Cepstral Coefficient Data |
| mfd | Multiframe Design |
| mfe | MobileFrame Enterprise Data |
| mff | EGI Metafile Format Data |
| mfg | Pro/ENGINEER Manufacturing Data |
| mfg | PTC Creo Manufacturing Process Data |
| mfi | MODFLOW Data Input Program |
| mfi | Windows 98 Resource Kit Data |
| mfil | World of Warcraft Software Update |
| mfj | MOBCAL Input Data |
| mfk | Memsoft OS/2 Database |
| mfl | MADRIX Fixture Library |
| mfl | ModFit LT Analysis Report |
| mfl | Mozilla Fastload File |
| mfn | MODFLOW Name Dataset |
| mfo | MediaFACE Online Saved File |
| mfo | MobileFrame Object Data |
| mfr | Moldflow Result |
| mfs | MetFS Encrypted File System |
