 Acer File Extensions |
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | #
| O | Object File (various) |
| O$$ | Output File (temporary usually) |
| O01 | Typhoon Voice File |
| OAB | MS Outlook Address Book |
| OAZ | OAZ Fax Document |
| OB$ | Microsoft Compressed OBJ, Decompress with UNPACK.EXE |
| OBD | Microsoft Office Binder Template |
| OBJ | Relocatable Object Code (various) |
| OBJ | Lightwave Object |
| OBR | Object Browser State File (Borland C++) |
| OBT | Microsoft Office Binder Template |
| OBV | ObjectScript |
| OBZ | Microsoft Office Binder Wizard |
| OCA | OLE Custom Control Library Information |
| OCF | Object Craft |
| OCR | Generic, Optical Character Recognition |
| OCX | ActiveX Control: A component of the Windows environment |
| OD1 | Omnis5 Database File (also .OD2, .OD3, etc.) |
| ODA | Used with OCX |
| ODA | Open Document Architecture Consortium Document |
| ODB | Microsoft Office 97 Binder Document |
| ODE | MS Office Object Data Embedding File |
| ODF | Open Document Interchange Format Document |
| ODF | BattleZone Cartographers Guild File |
| ODL | Visual C++ Type Library Source |
| ODS | MS Outlook Express Mailbox |
| ODT | Microsoft Office 97 Binder Document |
| OFC | Open Financial Connectivity File |
| OFD | ObjectView Form Definition |
| OFF | 3D Mesh Object File Format |
| OFF | Vector Graphic (Object File Format) |
| OFM | Adobe Font |
| OFN | Microsoft Office FileNew File |
| OFT | MS Outlook Item Template |
| OFX | Open Financial Exchange File |
| OGG | Ogg Vorbis Codec Compressed WAV File |
| OGX | Microsoft C++ Component Gallery Exported Classes and Resources |
| OKT | Oktalyzer Tracker Module |
| OLB | OLE Object Library |
| OLB | AUTOGEN File |
| OLB | VAX Object Library |
| OLD | Backup or Old Version of a File |
| OLE | OLE Object |
| OLI | Olivetti Text File |
| OLK | Microsoft Mail Mailbag Lock |
| OLN | Microsoft Visual C++ Outline |
| OLT | Microsoft Visual C++ Outline |
| OMF | Image File |
| ONX | Onyx Graphics Postershop File |
| OPC | Microsoft Office 97 Upgrade Wizard Clean-up |
| OPJ | OrCad Project File |
| OPL | Psion Organiser Programming Language Source File |
| OPO | OPL Output Executable File |
| OPT | Options (various) |
| OPT | Microsoft Developer Studio File |
| OPT | QEMM Optimise |
| OPW | Org Plus Organisational Chart |
| OPX | Microsoft Office Organisation Chart |
| OPX | OPL Extension DLL |
| OQY | MS Excel OLAP Query File |
| OR2 | Lotus Organiser 2 File |
| OR3 | Lotus Organiser 97 File |
| OR4 | Lotus Organizer 4 |
| ORA | Oracle 7 Configuration |
| ORC | Oracle 7 Script |
| ORC | MIDI File |
| ORG | Lotus Organiser File |
| OSS | Microsoft Office Search File |
| OST | Microsoft Exchange/Outlook Offline File |
| OTH | ".OtherFolder", Microsoft Power Toys Explorer tool |
| OTL | Super NoteTab Template File |
| OTX | Olivetti Olitext Document |
| OUT | Outlines or Output File (various) |
| OV1 | Program File - Overlay |
| OV2 | Program File - Overlay |
| OV3 | Program File - Overlay |
| OVL | Program File - Overlay |
| OVR | Program File - Overlay |
| OYZ | Lotus Approach alternate dBASE index |
| OZM | Sharp Organizer Memo Bank |
| OZP | Sharp Organizer Telephone Bank |