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

File Extensions O

  1. .O Object File (various)
  2. .O$$ Output File (temporary usually)
  3. .O01 Typhoon Voice File
  4. .OAB MS Outlook Address Book
  5. .OAZ OAZ Fax File
  6. .OBD MS Office Binder
  7. .OBJ Relocatable Object Code (various) Lightwave Object
  8. .OBZ MS Office Binder Wizard
  9. .OCA Control Typelib Cache
  10. .OCX Object Linking and Embedding (OLE) Control Extension
  11. .OD1 Omnis5 Database File (also OD2,OD3,etc.)
  12. .ODE MS Office Object Data Embedding File
  13. .ODF Open Document Interchange BattleZone Cartographers Guild File
  14. .ODL Visual C++ Type Library Source
  15. .ODS MS Outlook Express Mailbox
  16. .OFC Open Financial Connectivity File
  17. .OFF Vector Graphic (Object File Format) 3D Mesh Object File Format
  18. .OFM Adobe Font
  19. .OFN MS Office FileNew File
  20. .OFT MS Outlook Item Template
  21. .OFX Open Financial Exchange File
  22. .OGG Ogg Vorbis Codec Compressed WAV File
  23. .OKT Oktalyzer Tracker Module
  24. .OLB Object Library
  25. .OLD Old Version (sometimes used as a backup indicator)
  26. .OLE Object Linking and Embedding (OLE) Object
  27. .OLI Olivetti Text File
  28. .OMF Image File
  29. .OND Lotus Notes-related File (unverified)
  30. .ONX Onyx Graphics Postershop File
  31. .OPC Beta 44 Job File
  32. .OPJ OrCad Project File
  33. .OPL Psion Organiser Programming Language Source File
  34. .OPO OPL Output Executable File
  35. .OPT QEMM Optimize Options MS Developer Studio File
  36. .OPX MS Orgchart Organization Diagram OPL Extension DLL
  37. .OQY MS Excel OLAP Query File
  38. .OR2 Lotus Organiser 2 File
  39. .OR3 Lotus Organiser 97 File
  40. .ORA Oracle 7 Configuration
  41. .ORC MIDI File Oracle 7 Script
  42. .ORG Lotus Organiser File
  43. .ORI Original
  44. .OSS MS Office Saved Search
  45. .OST MS Exchange/Outlook Offline File
  46. .OTL Super NoteTab Template File
  47. .OUT Outlines or Output File (various)
  48. .OV1 Program File - Overlay
  49. .OV2 Program File - Overlay
  50. .OV3 Program File - Overlay
  51. .OVE Cakewalk Overture Score
  52. .OVL Program File - Overlay
  53. .OVR Program File - Overlay
  54. .OZM Sharp Organizer Memo Bank
  55. .OZP Sharp Organizer Telephone Bank

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