| nsvc | Formuler S Mini Channel List |
| nts | Lotus Traveler Bootstrap File |
| nvs | Ceedo SmartPlayer Package Configuration |
| nzp | Noise Ninja Noise Profile |
| oce | OCE Database Connection File |
| oco | Open Color Format Palette |
| officeui | Microsoft Office UI Customization |
| olk14mailaccount | Microsoft Office Outlook for Mac Accounts Data |
| olk14pref | Microsoft Office Outlook for Mac Preferences |
| olsr | Olsrd Configuration |
| omc | Origin Custom Menu Configuration |
| opax | Microsoft Office User Settings File |
| opn | Opera Optimizer Settings |
| ops | Microsoft Office Profile Settings |
| options | SE-SOFT Configuration |
| opts | Linux Configuration Options |
| ora | Oracle Configuration |
| osdx | Search Connector Description |
| ovpn | OpenVPN Configuration |
| p2k | WinPCD T2 Configuration |
| p3e | Adobe Photoshop Repousse Settings |
| p3l | Adobe Photoshop Light Preset |
| p3m | Adobe Photoshop Material Preset |
| p3r | Adobe Photoshop Render Settings Preset |
| pbk | Remote Access Phonebook Data |
| pbv | Corel Paint Shop Pro Bevel Preset |
| pc2 | Autodesk AutoCAD Plot Configuration |
| pc2 | Autodesk AutoCAD Plotter Configuration |
| pc3 | Autodesk AutoCAD Plot Configuration |
| pc3 | Autodesk AutoCAD Plotter Configuration |
