.NT | Microsoft Corporation | System Files | Windows NT Startup File | Microsoft Windows | Microsoft Corporation |
.NTF | Open Source | Font Files | Windows Font File | Microsoft Windows | Microsoft Corporation |
.NWS | Microsoft Corporation | Data Files | Windows Live Mail Newsgroup File | Microsoft Outlook Express | Microsoft Corporation |
.O | Microsoft Corporation | Developer Files | Compiled Object File | Microsoft Visual Studio | Microsoft Corporation |
.OAB | Microsoft Corporation | Data Files | Offline Address Book | Microsoft Outlook | Microsoft Corporation |
.OBD | Microsoft Corporation | Data Files | Office Binder Document | Microsoft Office | Microsoft Corporation |
.OBI | Microsoft Corporation | Settings Files | Outlook RSS Subscription File | Microsoft Outlook 2016 | Microsoft Corporation |
.OBT | Open Source | Settings Files | Openbox Theme File | Microsoft Binder | Microsoft Corporation |
.OCA | Microsoft Corporation | Developer Files | Custom Control Library Type File | Microsoft Visual Basic | Microsoft Corporation |
.OCR | URUWORKS | Uncommon Files | Subtitle Workshop OCR Script | Microsoft Notepad | Microsoft Corporation |
.OCSMEET | Microsoft Corporation | Data Files | Microsoft Lync Data | Microsoft Lync | Microsoft Corporation |
.OCX | Microsoft Corporation | Developer Files | ActiveX Control | Microsoft Visual Studio | Microsoft Corporation |
.OC_ | Microsoft Corporation | Compressed Files | Compressed ActiveX Control File | Microsoft Windows | Microsoft Corporation |
.ODC | Microsoft Corporation | Settings Files | Office Data Connection File | Microsoft Excel | Microsoft Corporation |
.ODCDATABASEFILE | Microsoft Corporation | Data Files | Microsoft Office File | Microsoft Office | Microsoft Corporation |
.ODCTABLECOLLECTIONFILE | Microsoft Corporation | Data Files | Microsoft Office Component | Microsoft Office | Microsoft Corporation |
.ODCTABLEFILE | Microsoft Corporation | Data Files | Microsoft Office File | Microsoft Office | Microsoft Corporation |
.ODF | Oracle Corporation | Uncommon Files | OpenDocument Formula | Microsoft Notepad | Microsoft Corporation |
.ODL | Microsoft Corporation | Developer Files | Object Description Language File | Microsoft Visual Studio | Microsoft Corporation |
.ODP | Oracle Corporation | Data Files | OpenDocument Presentation | Microsoft PowerPoint | Microsoft Corporation |
.ODS | Oracle Corporation | Spreadsheet Files | OpenDocument Spreadsheet | Microsoft Excel | Microsoft Corporation |
.ODT | Oracle Corporation | Text Files | OpenDocument Text Document | Microsoft Word | Microsoft Corporation |
.OEACCOUNT | Microsoft Corporation | Data Files | Windows Mail Account File | Microsoft Mail | Microsoft Corporation |
.OEM | Microsoft Corporation | Settings Files | Original Equipment Manufacturer Setup File | Microsoft Windows | Microsoft Corporation |
.OFC | Microsoft Corporation | Data Files | Open Financial Connectivity File | Microsoft Money | Microsoft Corporation |
.OFFICEUI | Microsoft Corporation | Settings Files | Microsoft Office UI Customization File | Microsoft Office | Microsoft Corporation |
.OFN | Microsoft Corporation | Data Files | Systems Management Server Offer Creation Notification File | Microsoft Systems Management Server | Microsoft Corporation |
.OFT | Microsoft Corporation | Data Files | Outlook File Template | Microsoft Outlook | Microsoft Corporation |
.OFX | Intuit, Inc. | Data Files | Open Financial Exchange File | Microsoft Money | Microsoft Corporation |
.OGX | Xiph.Org | Video Files | Ogg Vorbis Multiplexed Media File | Microsoft Windows Media Player | Microsoft Corporation |
.OHP | Microsoft Corporation | Data Files | MS-DOS 7 File | MS-DOS | Microsoft Corporation |
.OLB | Microsoft Corporation | Uncommon Files | OLE Object Library | Microsoft Excel | Microsoft Corporation |
.OLE | Microsoft Corporation | Data Files | Microsoft Object Linking And Embedding Data | Microsoft Windows | Microsoft Corporation |
.OLK | Microsoft Corporation | Data Files | Outlook Address Book File | Microsoft Word | Microsoft Corporation |
.OLM | Microsoft Corporation | Data Files | Mac Outlook Database File | Microsoft Outlook 2016 | Microsoft Corporation |
.OLS | Microsoft Corporation | Data Files | Microsoft Office List Shortcut | Microsoft Office | Microsoft Corporation |
.OMP | MatchWare | Page Layout Files | OpenMind Windows Document | Microsoft Access | Microsoft Corporation |
.ONE | Microsoft Corporation | Data Files | OneNote Document | Microsoft OneNote | Microsoft Corporation |
.ONEBIN | Microsoft Corporation | Temporary Files | OneNote Data | Microsoft OneNote | Microsoft Corporation |
.ONECACHE | Microsoft Corporation | Temporary Files | Microsoft OneNote Cache File | Microsoft OneNote | Microsoft Corporation |
.ONEPKG | Microsoft Corporation | Backup Files | Microsoft OneNote Package File | Microsoft OneNote | Microsoft Corporation |
.ONETOC | Microsoft Corporation | Settings Files | Microsoft OneNote Table Of Contents | Microsoft OneNote | Microsoft Corporation |
.ONETOC2 | Microsoft Corporation | Settings Files | Microsoft OneNote Table Of Contents File | Microsoft OneNote | Microsoft Corporation |
.OPS | Microsoft Corporation | Settings Files | Office Profile Settings File | Microsoft Office | Microsoft Corporation |
.OPT | LexisNexis | Database Files | Concordance Database File | Microsoft Visual Studio | Microsoft Corporation |
.OPUS | Open Source | Audio Files | Opus Audio File | Microsoft Windows Media Player | Microsoft Corporation |
.OPX | Insperity Business Services | Data Files | OrgPlus Organizational Chart | Microsoft Office | Microsoft Corporation |
.OQY | Microsoft Corporation | Database Files | Excel OLAP Query File | Microsoft Excel | Microsoft Corporation |
.ORDEREDTEST | Microsoft Corporation | Developer Files | Visual Studio Ordered Test File | Microsoft Visual Studio | Microsoft Corporation |
.ORF | Olympus Corporation | Camera Raw Files | Olympus RAW File | ACD Systems Canvas | Microsoft Corporation |
.ORP | PV & Associates | Data Files | WinSLAM File | Microsoft Translator | Microsoft Corporation |
.OSC | OpenStreetMap | GIS Files | OpenStreetMap Change File | Microsoft Windows | Microsoft Corporation |
.OSD | Microsoft Corporation | Data Files | Open Software Description Data | Microsoft Application Virtualization | Microsoft Corporation |
.OSDX | Microsoft Corporation | Settings Files | Search Connector Description File | Microsoft Windows | Microsoft Corporation |
.OSS | Microsoft Corporation | Settings Files | Microsoft Outlook Saved Search File | Microsoft Outlook | Microsoft Corporation |
.OST | Microsoft Corporation | Uncommon Files | Outlook Offline Data File | Microsoft Outlook 2016 | Microsoft Corporation |
.OTM | Microsoft Corporation | Executable Files | Outlook Macro File | Microsoft Word | Microsoft Corporation |
.OTP | Oracle Corporation | Data Files | OpenDocument Presentation | Microsoft PowerPoint | Microsoft Corporation |
.OUT | Open Source | Executable Files | Compiled Executable File | Microsoft Notepad | Microsoft Corporation |
.OV3 | Microsoft Corporation | System Files | DOS Overlay File | MS-DOS | Microsoft Corporation |
.OXPS | Microsoft Corporation | Page Layout Files | OpenXPS File | Microsoft XPS Viewer | Microsoft Corporation |
.P10 | Open Source | Uncommon Files | Certificate Request File | Microsoft Outlook | Microsoft Corporation |
.P12 | RSA Laboratories | Web Files | Personal Information Exchange File | Certificate Manager Tool | Microsoft Corporation |
.P2P | Microsoft Corporation | Uncommon Files | FolderShare Placeholder File | FolderShare | Microsoft Corporation |
.P5 | Larry Wall | Developer Files | Perl Source Code | Microsoft Notepad | Microsoft Corporation |
.P5X | Microsoft Corporation | System Files | Microsoft Windows System Data | Microsoft Windows | Microsoft Corporation |
.P7 | Open Source | Web Files | PKCS #7 Digital Certificate File | Certificate Manager Tool | Microsoft Corporation |
.P7B | Microsoft Corporation | Web Files | PKCS #7 Certificate File | Microsoft Windows | Microsoft Corporation |
.P7C | Microsoft Corporation | Web Files | PKCS #7 Certificate File | Microsoft Windows | Microsoft Corporation |
.P7S | Unknown Developer | Encoded Files | PKCS #7 Signature File Format | Microsoft Outlook Express | Microsoft Corporation |
.P7X | Microsoft Corporation | Data Files | Packed Digital Signature File | Microsoft Visual Studio | Microsoft Corporation |
.PAB | Microsoft Corporation | Data Files | Personal Address Book | Microsoft Outlook Express | Microsoft Corporation |
.PAC | NetScape | Web Files | Proxy Auto-Config File | Internet Explorer | Microsoft Corporation |
.PACKAGE | Electronic Arts | Game Files | Electronic Arts Game Package File | Microsoft Visual Studio | Microsoft Corporation |
.PAG | Microsoft Corporation | Data Files | Visual Basic Property PAGe File | Microsoft Visual Basic | Microsoft Corporation |
.PANIC | Open Source | System Files | Kernel Panic File | Microsoft Word | Microsoft Corporation |
.PANO | Microsoft Corporation | Raster Image Files | Camera Panoramic Picture | Microsoft OneDrive | Microsoft Corporation |
.PARTIAL | Microsoft Corporation | Uncommon Files | Internet Explorer Partially Downloaded File | Internet Explorer | Microsoft Corporation |
.PBI | The FreeBSD Community | Compressed Files | PC BSD Installer Package | Microsoft Visual Studio | Microsoft Corporation |
.PBK | Microsoft Corporation | Data Files | Dial-Up Phone Book File | Microsoft Windows | Microsoft Corporation |
.PBM | Unknown Developer | Raster Image Files | Portable Bitmap Image | Microsoft Word | Microsoft Corporation |
.PBO | Bohemia Interactive | Game Files | Packed Bohemia Object | Microsoft Visual Studio | Microsoft Corporation |
.PBR | Sybase, Inc | Data Files | PowerBuilder Resource File | Microsoft Publisher | Microsoft Corporation |
.PBX | Sybase, Inc | Developer Files | PowerBuilder Extension File | Microsoft Outlook Express | Microsoft Corporation |
.PCC | Electronic Arts | Game Files | Mass Effect Package | Microsoft Notepad | Microsoft Corporation |
.PCF | Blackstrip Studios | Font Files | PaintCAD Font | Microsoft Windows | Microsoft Corporation |
.PCH | MSC Software | Data Files | Nastran Punch Output File | Microsoft Visual Studio | Microsoft Corporation |
.PCI | Microsoft Corporation | System Files | PCI Miniport Data | Microsoft Windows | Microsoft Corporation |
.PCK | Microsoft Corporation | System Files | System Center Configuration Manager Package File | Microsoft system center configuration manager | Microsoft Corporation |
.PCP | Microsoft Corporation | Developer Files | Windows Installer Patch Creation Properties File | Microsoft Windows SDK | Microsoft Corporation |
.PCS | Pfaff | CAD Files | Pfaff Embroidery File | Microsoft Office | Microsoft Corporation |
.PCX | ZSoft Corporation | Raster Image Files | Paintbrush Bitmap Image File | Microsoft Windows Picture and Fax Viewer | Microsoft Corporation |
.PD4 | Jan van Wijk | Backup Files | DFSee Partition Table And Boot Sector Backup | Windows Photo Gallery | Microsoft Corporation |
.PD5 | Microsoft Corporation | Data Files | Windows Live Photo Gallery Information File | Windows Photo Gallery | Microsoft Corporation |
.PDB | Various Developers | Data Files | Program Database | Microsoft Visual Studio | Microsoft Corporation |
.PDM | Sybase, Inc | Database Files | PowerDesigner Database File | Microsoft Visual Studio | Microsoft Corporation |
.PDR | Microsoft Corporation | System Files | Windows Port Driver | Windows Control Panel | Microsoft Corporation |
.PDT | Microsoft Corporation | Data Files | InkWriter Note Taker Template File | Windows Mobile | Microsoft Corporation |
.PDW | AcaClone | Data Files | pDRAW32 DNA File | Microsoft Word | Microsoft Corporation |
.PDZ | ProntoForms | Page Layout Files | ProntoDoc For Word Structured Text Document Template | Microsoft Word | Microsoft Corporation |