| .mct |
Windows Live Messenger Data File |
| .mad |
Electronic Arts Madcow Movie File |
| .mrb |
Multiple Resolution Bitmap File |
| .ms-tnef |
MS Transport Neutral Encapsulation Format |
| .mdbhtml |
Microsoft Access Database HTML File |
| .msh1xml |
Monad Display Configuration File |
| .nt |
Windows NT Startup File |
| .nfo |
System Information File |
| .nk2 |
Outlook 2002 Nickname File |
| .nick |
Outlook 2000 Nickname File |
| .ndf |
SQL Server Secondary Database File |
| .nls |
NetLogo Source File |
| .ncb |
Visual C++ IntelliSense Database |
| .nws |
Windows Live Mail Newsgroup File |
| .natvis |
Natvis VC++ Debugger Visualization File |
| .nav |
Id Tech 3 Bot Navigation File |
| .nbt |
Minecraft Named Binary Tag File, Nero BackItUp Template File |
| .nst |
NoiseTracker Module |
| .nch |
Outlook Express Folder File |
| .otf |
OpenType Font |
| .ocx |
ActiveX Control |
| .ods |
OpenDocument Spreadsheet |
| .oeaccount |
Windows Mail Account File |
| .obi |
Outlook RSS Subscription File |