O File Extensions
Browse file types with extensions beginning with O.
| Extension | File Type | Popularity |
|---|---|---|
| .O | Compiled C Object File | 3.8 |
| .OAB | Offline Address Book | 3.5 |
| .OAF | Obsidian Archive File | 2.0 |
| .OAM | Adobe Edge Animate Widget File | 3.8 |
| .OAP | OutSystems Application Package | 2.3 |
| .OAR | OpenSimulator Archive | 3.5 |
| .OAT | Android Optimized Application File | 3.2 |
| .OB! | Orbit Downloader Incomplete Download | 4.2 |
| .OB2 | Oberon-2 Source Code File | 3.7 |
| .OBB | Android Opaque Binary Blob File | 4.0 |
| .OBD | Office Binder Document | 3.6 |
| .OBF | OsmAnd Offline Map File | 3.6 |
| .OBI | Outlook RSS Subscription File | 3.9 |
| .OBJ | Wavefront 3D Object File | 3.9 |
| .OBJ | Relocatable Object Code | 3.4 |
| .OBJECTION | Objection.lol Project | 3.8 |
| .OBK | Backup File | 3.5 |
| .OBK | OrangeCD Backup File | 1.0 |
| .OBL | openCanvas Brush File | 2.0 |
| .OBML | Opera Mini Saved Webpage | 3.6 |
| .OBML15 | Opera Mini Saved Webpage | 4.0 |
| .OBML16 | Opera Mini Saved Webpage | 3.7 |
| .OBP | Bryce Object File | 4.1 |
| .OBT | Openbox Theme File | 4.0 |
| .OBW | Superior Drummer Sounds File | 3.2 |
| .OBZ | Compressed 3D Object File | 3.7 |
| .OC3 | openCanvas 3 Event File | 3.3 |
| .OC4 | openCanvas 4 Event File | 4.0 |
| .OC5 | openCanvas 5 Event File | 3.0 |
| .OCA | Custom Control Library Type File | 3.5 |
| .OCB | Oxygen Forensics Cloud Backup | 2.0 |
| .OCC | Oceanic DataPool File | 3.0 |
| .OCD | OCAD Map File | 3.0 |
| .OCE | Open Catalog Extension Connection File | 2.3 |
| .OCI | openCanvas Image | 3.3 |
| .OCIMF | OCIMF HVPQ File | 2.0 |
| .OCR | FAXGrapper Fax Text File | 2.2 |
| .OCR | Subtitle Workshop OCR Script | 3.9 |
| .OCT | Radiance Octree File | 2.7 |
| .OCTEST | Xcode Objective-C Unit Test Bundle | 3.4 |
| .OCX | ActiveX Control | 3.9 |
| .OD | Mascopt Graph Request File | 3.3 |
| .ODB | OpenDocument Database | 3.9 |
| .ODB | Abaqus Output Database | 2.9 |
| .ODB | Oxygen Forensics Desktop Backup | 1.0 |
| .ODC | Office Data Connection File | 3.8 |
| .ODC | OpenDocument Chart File | 2.5 |
| .ODEX | Optimized Dalvik Executable | 3.5 |
| .ODF | OpenDocument Formula | 3.8 |
| .ODF | Open Document File | 2.9 |
| .ODF | Battlezone Object Definition File | 2.6 |
| .ODG | OpenDocument Graphic File | 3.6 |
| .ODI | OpenDocument Image | 2.7 |
| .ODIF | Open Document Interchange Format | 3.3 |
| .ODIN | Locky Ransomware Encrypted File | 4.0 |
| .ODKBUILD | ODK Build Form | 3.0 |
| .ODL | Object Description Language File | 3.0 |
| .ODL | OneDrive Event Log | 2.5 |
| .ODLGZ | Gzipped OneDrive Event Log | 3.5 |
| .ODLSENT | Sent OneDrive Event Log | 2.0 |
| .ODM | OverDrive Media File | 3.1 |
| .ODM | OpenDocument Master Document | 3.8 |
| .ODO | Online Operating System Write Document | 3.2 |
| .ODOC | Synology Office Document Pointer | 3.0 |
| .ODP | OpenDocument Presentation | 3.8 |
| .ODP | Organ Definition Project | 2.0 |
| .ODR | osu!droid Replay | 2.8 |
| .ODS | OpenDocument Spreadsheet | 3.5 |
| .ODS | Outlook Express 5 Mailbox | 3.0 |
| .ODT | OpenDocument Text Document | 3.5 |
| .ODT | OOMMF Data Table | 3.0 |
| .ODT | Origin Dialog Theme | 2.8 |
| .ODTTF | Obfuscated OpenType Font | 3.7 |
| .ODX | BizTalk Server Orchestration File | 2.0 |
| .OE6 | openCanvas 6 Event File | 2.5 |
| .OEACCOUNT | Windows Mail Account File | 3.5 |
| .OEB | Outlook Express Backup Wizard File | 2.5 |
| .OEB | Open eBook File | 3.0 |
| .OEBZIP | Zipped Open eBook File | 2.0 |
| .OEM | OEM Setup File | 3.7 |
| .OEM | OEMEdit Save File | 2.5 |
| .OESAVESTATE | OpenEmu Saved Game | 3.0 |
| .OEX | Opera Extension | 4.0 |
| .OFB | Oxygen Forensics Extractor Backup | 2.0 |
| .OFBR | Oxygen Forensics Important Data Backup | 2.0 |
| .OFBX | Oxygen Forensics Detective Backup | 3.5 |
| .OFC | Open Financial Connectivity File | 3.4 |
| .OFD | OfficeForms Document | 3.3 |
| .OFF | Object File Format | 3.8 |
| .OFFICEUI | Microsoft Office UI Customization File | 4.3 |
| .OFL | Ots File List | 2.6 |
| .OFM | Melco Embroidery File | 1.7 |
| .OFM | OmniForm Form | 1.8 |
| .OFP | Origin Function Plot Theme File | 3.4 |
| .OFR | OptimFROG Audio File | 2.0 |
| .OFR | SMS Offer Manager File | 3.0 |
| .OFT | Outlook File Template | 3.5 |
| .OFX | Open Financial Exchange File | 3.3 |
| .OFX | OpenFX Plugin | 3.0 |
| .OGA | Ogg Vorbis Audio File | 3.7 |
| .OGF | S.T.A.L.K.E.R. Model File | 3.2 |
| .OGG | Ogg Vorbis Audio | 3.9 |
| .OGG | Origin Graph File | 2.5 |
| .OGGSTR | Godot Engine Ogg Audio File | 3.3 |
| .OGGU | Origin Unicode Graph File | 3.7 |
| .OGM | Ogg Media File | 3.5 |
| .OGM | Origin Matrix File | 3.2 |
| .OGMO | OGMO Editor Project | 4.0 |
| .OGMU | Origin Unicode Matrix File | 2.5 |
| .OGNC | Dynamic Web Page | 3.0 |
| .OGS | Origin LabTalk Script File | 3.5 |
| .OGS | Origons Movie Data File | 1.0 |
| .OGV | Ogg Video | 3.6 |
| .OGW | Origin Workbook File | 2.5 |
| .OGWU | Origin Unicode Workbook File | 3.0 |
| .OGX | Ogg Vorbis Multiplexed Media File | 3.5 |
| .OGZ | Cube 2 Map File | 4.3 |
| .OIF | Origin Import Filter File | 1.7 |
| .OIR | FV3000 Specimen Image | 2.0 |
| .OIS | Origin Analyses Theme File | 2.4 |
| .OIV | OpenIV Mod Package File | 4.1 |
| .OKT | Oktalyzer Module | 3.3 |
| .OL | Valve Hammer Object Layout File | 3.6 |
| .OLA | Online Access File | 4.0 |
| .OLB | OLE Object Library | 3.8 |
| .OLB | OrCAD Symbol Library File | 3.1 |
| .OLD | Backup File | 3.7 |
| .OLK | Outlook Address Book File | 4.1 |
| .OLK14CATEGORY | Outlook Category File | 1.7 |
| .OLK14CONTACT | Outlook Contact File | 2.0 |
| .OLK14EVENT | Outlook Calendar Event File | 2.0 |
| .OLK14GROUP | Outlook Group File | 2.0 |
| .OLK14MAILACCOUNT | Outlook Mail Account File | 1.5 |
| .OLK14MESSAGE | Outlook Message File | 3.3 |
| .OLK14MSGATTACH | Outlook 2011 Email Message Attachment File | 2.0 |
| .OLK14MSGSOURCE | Outlook Email Message Data File | 3.7 |
| .OLK14NOTE | Outlook Note File | 2.0 |
| .OLK14PREF | Outlook Preferences File | 2.0 |
| .OLK14SIGNATURE | Outlook Signature File | 3.0 |
| .OLK14TASK | Outlook Task File | 1.0 |
| .OLK15MESSAGE | Outlook 15 Message Header | 4.0 |
| .OLK15MSGATTACH | Outlook 15 Attachment Data | 2.0 |
| .OLK15MSGSOURCE | Outlook 15 Message | 3.0 |
| .OLL | TrialDirector Object Load List | 3.0 |
| .OLM | Mac Outlook Database File | 4.1 |
| .OLP | Office Live Package | 3.5 |
| .OLS | Microsoft Office List Shortcut | 3.0 |
| .OLT | Orbit Downloads List | 2.5 |
| .OMA | Sony OpenMG Music File | 3.6 |
| .OMCS | Office Manager Access File | 3.5 |
| .OMF | Open Media Framework File | 3.6 |
| .OMF | OMF Interchange Image File | 2.3 |
| .OMFL | Open Multiple Files File List | 3.4 |
| .OMG | Image File | 3.4 |
| .OMG | OpenMG Audio File | 4.0 |
| .OML | OutSystems Modeling Language File | 1.3 |
| .OMO | OMake Object File | 3.4 |
| .OMOD | Oblivion Mod Archive | 3.3 |
| .OMP | Office Manager Document Archive | 3.3 |
| .OMP | OpenMind Windows Document | 3.0 |
| .OMS | HP Printer Substrate Presets Package File | 3.0 |
| .OMWADDON | OpenMW Plug-in | 3.5 |
| .OMX | OtsAV Media Library Information File | 3.4 |
| .ONC | Open Network Configuration | 3.0 |
| .OND | Lotus Notes Encapsulated Memo File | 2.2 |
| .ONE | OneNote Document | 3.5 |
| .ONEPKG | Microsoft OneNote Package | 3.8 |
| .ONETOC | Microsoft OneNote Table of Contents | 1.7 |
| .ONETOC2 | Microsoft OneNote Table of Contents | 3.8 |
| .ONT | theWord Bible Text Module | 3.4 |
| .ONTX | theWord Encrypted Bible Text Module | 4.0 |
| .OO3 | OmniOutliner 3 File | 3.7 |
| .OO3TEMPLATE | OmniOutliner Template | 2.5 |
| .OOK | Arachne Batch Script | 2.7 |
| .OP | OpenPAT Report | 3.1 |
| .OP2 | Nastran Output File | 3.5 |
| .OP4 | Nastran Output File | 3.5 |
| .OPAL | Microsoft Office User Settings File | 3.0 |
| .OPAX | Microsoft Office User Settings File | 2.6 |
| .OPB | Outplayed Backup File | 3.0 |
| .OPBACC | OpenBacc Project | 1.0 |
| .OPD | OmniPage Document | 3.4 |
| .OPD | Durango Document | 2.5 |
| .OPDOWNLOAD | Opera Partially Downloaded File | 4.1 |
| .OPEICO | Opeico Text File | 3.6 |
| .OPENBSD | OpenBSD Readme File | 2.4 |
| .OPF | Open Packaging Format File | 3.5 |
| .OPF | FlipAlbum File | 3.8 |
| .OPF | FlipViewer FlipBook File | 3.6 |
| .OPJ | OrCAD Project File | 3.3 |
| .OPJ | Origin Project | 3.1 |
| .OPJU | Origin Unicode Project | 3.8 |
| .OPK | GCW Zero Open Package | 4.0 |
| .OPLC | Nokia Operator Logo File | 4.0 |
| .OPLUSDOWNLOAD | OnePlus Downloaded File | 3.0 |
| .OPM | Object Playground Mod | 3.7 |
| .OPML | Outline Processor Markup Language File | 3.6 |
| .OPS | Office Profile Settings File | 3.6 |
| .OPT | Options File | 3.7 |
| .OPT | Opterecenja File | 4.3 |
| .OPT | AGT Game Data File | 2.8 |
| .OPTIONS | SE-SOFT Configuration File | 3.3 |
| .OPTS | Linux Configuration Options File | 3.4 |
| .OPUS | Opus Audio | 3.6 |
| .OPX | OrgPlus Org Chart | 3.9 |
| .OPX | FlipAlbum Photo Album File | 2.3 |
| .OPZ | Zipped FlipViewer FlipBook | 3.0 |
| .OQY | Microsoft Excel OLAP Query | 3.7 |
| .OR2 | Lotus Organizer 2 File | 3.0 |
| .OR3 | IBM Lotus Organizer 97 File | 1.3 |
| .OR4 | IBM Lotus Organizer 97 GS Database | 3.0 |
| .OR5 | Lotus Organizer 5 File | 2.5 |
| .OR6 | Lotus Organizer 6 File | 3.0 |
| .ORA | Oracle Database Configuration File | 3.2 |
| .ORA | OpenRaster Image File | 3.2 |
| .ORB | Original eBook Reader File | 3.0 |
| .ORC | Voyetra Digital Orchestrator File | 1.0 |
| .ORDEREDTEST | Visual Studio Ordered Test File | 3.0 |
| .ORE | Ore Executable File | 1.9 |
| .ORF | Olympus RAW File | 3.6 |
| .ORG | Lotus Organizer File | 3.5 |
| .ORG | Organya Music File | 3.2 |
| .ORG | Emacs Org Text Document | 3.8 |
| .ORGAN | GrandOrgue Organ Sample Set | 3.6 |
| .ORI | Original File | 2.9 |
| .ORIG | Original File | 3.9 |
| .ORRS | Deliveries Package Tracker Backup | 2.0 |
| .ORT | Rich Text Editor Document | 3.0 |
| .ORV | Oracom Video File | 3.0 |
| .ORW | OpenRAW File | 2.0 |
| .ORX | RadiantOne VDS Database Schema | 3.0 |
| .OS | ObjectScript Source File | 3.2 |
| .OSAX | AppleScript Scripting Addition | 3.0 |
| .OSB | OpenStreetMap Binary Map File | 2.5 |
| .OSB | Osu! Storyboard File | 4.0 |
| .OSC | OpenStreetMap Change File | 3.9 |
| .OSC | Obix Source Code File | 1.5 |
| .OSDX | Search Connector Description File | 3.9 |
| .OSF | OsmAnd Package | 2.0 |
| .OSK | osu! Skin File | 4.4 |
| .OSM | OpenStreetMap Map | 3.8 |
| .OSP | OpenShot Video Editor Project File | 3.6 |
| .OSR | osu! Replay File | 4.6 |
| .OSS | Microsoft Outlook Saved Search File | 4.3 |
| .OST | Outlook Offline Data File | 3.4 |
| .OSU | Osu! Script | 3.8 |
| .OSX | PowerPC Executable File | 3.4 |
| .OSZ | osu! Beatmap File | 4.4 |
| .OSZ | OpenLP Service File | 2.8 |
| .OSZ2 | osu! Submitted Beatmap File | 3.5 |
| .OT | theWord Old Testament Text Module | 2.8 |
| .OTA | OTA Bitmap Image | 3.9 |
| .OTA | OTA Ringtone File | 2.0 |
| .OTB | Nokia Over The Air Bitmap Image | 3.8 |
| .OTC | OpenDocument Chart Template | 1.5 |
| .OTF | OpenType Font | 3.8 |
| .OTF | OpenDocument Formula Template | 2.8 |
| .OTF | OpenTuft Tufting Design File | 2.4 |
| .OTG | OpenDocument Graphic Template | 3.4 |
| .OTH | OpenDocument HTML Template | 2.8 |
| .OTH | Origin Graph Theme File | 1.0 |
| .OTI | OpenDocument Image Template | 3.3 |
| .OTL | NoteTab Outline File | 3.0 |
| .OTLN | Opal Outline File | 3.9 |
| .OTM | Outlook Macro File | 3.5 |
| .OTM | Origin Matrix Template | 3.5 |
| .OTMU | Origin Unicode Matrix Template | 4.0 |
| .OTP | OpenDocument Presentation Template | 3.6 |
| .OTP | Origin Graph Template | 3.5 |
| .OTPU | Origin Unicode Graph Template | 4.0 |
| .OTRKEY | OnlineTvRecorder Encoded Video File | 3.0 |
| .OTS | OpenDocument Spreadsheet Template | 3.8 |
| .OTS | OtsAV Album File | 2.8 |
| .OTT | OpenDocument Document Template | 3.6 |
| .OTW | Origin Workbook Template | 3.5 |
| .OTWU | Origin Unicode Workbook Template | 2.0 |
| .OTX | theWord Encrypted Old Testament Text Module | 1.5 |
| .OTZ | OpenLP Theme File | 3.3 |
| .OUT | Output File | 3.1 |
| .OUT | Compiled Executable File | 3.9 |
| .OV2 | TomTom Points of Interest Database | 3.0 |
| .OVA | Open Virtual Appliance | 3.8 |
| .OVA | Octava Musical Score | 3.2 |
| .OVE | Overture Musical Score | 2.8 |
| .OVERLAY | Streamlabs Desktop Overlay | 3.0 |
| .OVEX | Overture 5 Musical Score | 3.0 |
| .OVF | Open Virtualization File | 3.8 |
| .OVH | OMSI Vehicle Configuration File | 3.3 |
| .OVL | Rollercoaster Tycoon 3 Data File | 3.6 |
| .OVL | Jurassic World Evolution Model Archive | 2.0 |
| .OVOLOG | ooVoo Log File | 3.4 |
| .OVP | The Overlay Maker Package File | 2.8 |
| .OVPN | OpenVPN Configuration File | 4.1 |
| .OVR | The Overlay Maker Overlay File | 2.9 |
| .OVW | Logic Pro Overview File | 3.8 |
| .OVW | Cubase WAVE Overview File | 2.7 |
| .OVX | Object-based Visual Application Language File | 1.0 |
| .OW | Free Pascal 1.0.x Compiled Object | 3.0 |
| .OWC | OutWit Catch Database | 2.0 |
| .OWG | OutWit Gear Database | 2.0 |
| .OWL | OWL Source Code File | 3.3 |
| .OWM | OutWit XML Mashup File | 3.7 |
| .OWX | OutWit Hub Automator File | 2.0 |
| .OXPS | OpenXPS File | 3.6 |
| .OXT | Apache OpenOffice Extension | 3.8 |
| .OXYGENE | Oxygene Project File | 3.5 |
| .OYX | Approach Alternate Database Index | 2.3 |
| .OZ | Opera Job Management Compressed File | 3.5 |
| .OZB | MU Online Image File | 3.0 |
| .OZIP | OPPO Smartphone Firmware Update | 3.4 |
| .OZJ | MU Online Image File | 3.8 |
| .OZOCODE | Ozobot Program | 3.5 |
| .OZT | MU Online Image File | 3.5 |