I File Extensions
Browse file types with extensions beginning with I.
| Extension | File Type | Popularity |
|---|---|---|
| .I | Visual Studio Intermediate File | 3.6 |
| .I | INTERCAL Source File | 4.3 |
| .I00 | DVD Shrink Part 1 File | 3.1 |
| .I01 | DVD Shrink Part 2 File | 3.8 |
| .I02 | DVD Shrink Part 3 File | 4.0 |
| .I3D | Houdini Image 3D File | 3.6 |
| .I3PACK | Point Blank Game Data | 4.5 |
| .I5Z | IUCLID 5 Import/Export File | 3.5 |
| .I6 | Inform 6 Source Code File | 2.0 |
| .I6T | Inform 6 Template | 2.0 |
| .I7 | Inform 7 Source Code File | 2.0 |
| .I7X | Inform 7 Extension Source Code File | 2.0 |
| .I7XP | Inform 7 Extension Project | 3.5 |
| .IAA | INTUS Audio Archive | 3.5 |
| .IADACTION | iAd Producer Plugin Action Template | 2.0 |
| .IADCLASS | iAd Producer Plugin Class Description File | 4.3 |
| .IADCOMPONENT | iAd Producer Plugin Component File | 3.3 |
| .IADPAGE | iAd Producer Plugin Page Template | 3.7 |
| .IADPLUG | iAd Producer Plugin | 2.0 |
| .IADPROJ | iAd Producer Project | 3.2 |
| .IADSTYLE | iAd Producer Plugin Style Template | 3.0 |
| .IAF | Outlook Internet Account File | 2.7 |
| .IAM | Inventor Assembly | 3.7 |
| .IAS | Intermodulation Analysis System File | 2.2 |
| .IAVATAR | iClone Avatar | 4.3 |
| .IB | InterBase Database | 3.3 |
| .IB2 | IncrediBots 2 Saved Challenge File | 1.0 |
| .IB3 | IncrediBots 3 Saved Challenge File | 1.0 |
| .IBA | iBooks Author Document | 3.4 |
| .IBA | Lectra Clothing Design Pieces File | 4.4 |
| .IBADR | IsoBuster Address File | 3.0 |
| .IBATEMPLATE | iBooks Author Document Template | 3.0 |
| .IBB | ImgBurn Project File | 2.8 |
| .IBCD | InstantBingoCard Document | 3.0 |
| .IBCH | IncrediBots Challenge File | 2.0 |
| .IBD | MySQL InnoDB Table | 3.5 |
| .IBDAT | IsoBuster Data File | 3.6 |
| .IBG | ImgBurn Graph File | 3.5 |
| .IBK | IncrediMail Account Backup File | 3.7 |
| .IBOOKS | Multi-Touch iBook | 3.9 |
| .IBP | IsoBuster Managed Image Information | 3.8 |
| .IBPLUGIN | Interface Builder Plug-in | 3.3 |
| .IBQ | IsoBuster Managed Image | 2.8 |
| .IBRE | IncrediBots Replay File | 3.4 |
| .IBRO | IncrediBots Robot File | 3.5 |
| .IBT | Texture and Model File | 3.7 |
| .IC1 | Low Resolution Imagic Graphics File | 1.0 |
| .IC2 | Medium Resolution Imagic Graphics File | 1.0 |
| .IC3 | High Resolution Imagic Graphics File | 1.0 |
| .IC3D | IC3D Scene File | 3.0 |
| .ICA | Citrix ICA File | 3.4 |
| .ICA | Image Object Content Architecture File | 3.1 |
| .ICAL | iCalendar File | 3.3 |
| .ICALENDAR | iCalendar File | 3.5 |
| .ICALEVENT | iCal Event File | 2.0 |
| .ICALTODO | iCal To Do File | 2.0 |
| .ICAP | InCopy Package File | 4.0 |
| .ICB | Targa ICB Bitmap Image | 3.0 |
| .ICBU | Calendar Backup File | 2.0 |
| .ICC | ICC Profile | 3.4 |
| .ICD | Installable Client Driver File | 3.7 |
| .ICD | SafeDisc Encrypted Program | 3.6 |
| .ICD | IronCAD 2D Drawing File | 3.9 |
| .ICDB | Icaros Thumbnail Database | 2.0 |
| .ICE | ICE Compressed Archive | 4.0 |
| .ICF | Zoom Router Configuration File | 1.7 |
| .ICG | Image Comparer Gallery File | 2.7 |
| .ICHAT | iChat Saved Chat Log | 3.8 |
| .ICL | Windows Icon Library File | 3.2 |
| .ICLAN | 24clan Inject Settings | 1.0 |
| .ICM | Image Color Matching Profile | 4.0 |
| .ICMA | InCopy Assignment File | 4.0 |
| .ICML | InCopy Document | 3.0 |
| .ICMOD | Inner Core Minecraft PE Mod File | 3.8 |
| .ICMT | InCopy Template | 3.0 |
| .ICN | Windows Icon File | 3.7 |
| .ICNS | macOS Icon Resource | 4.2 |
| .ICO | Icon File | 4.1 |
| .ICON | Icon Image | 4.3 |
| .ICONPACKAGE | IconPackager Theme File | 4.2 |
| .ICONSET | Mac OS X Icon Set Folder | 3.5 |
| .ICONTAINER | CandyBar iContainer File | 3.0 |
| .ICPR | IconUtils Project File | 2.0 |
| .ICR | Image Comparer Results File | 4.3 |
| .ICS | Calendar File | 3.5 |
| .ICS | IronCAD 3D Scene | 3.3 |
| .ICS | IC Recorder Sound File | 3.2 |
| .ICST | InCopy Document Preset File | 4.0 |
| .ICURSORFX | iCursor Effect File | 3.5 |
| .ID | Lotus Notes User ID File | 4.0 |
| .ID2 | Windows Live Messenger Emoticon File | 3.0 |
| .ID3TAG | MP3 Skype Recorder Temporary File | 1.0 |
| .IDAP | Adobe InDesign Assignment Package | 3.5 |
| .IDB | Visual Studio Intermediate Debug File | 3.7 |
| .IDB | IDA Database File | 2.9 |
| .IDC | Internet Database Connector File | 2.8 |
| .IDCL | Inventor Desktop Content Library File | 2.0 |
| .IDDX | Static Default File | 1.0 |
| .IDE | Inventor iFeature | 4.0 |
| .IDE | GTA Item Definition File | 4.2 |
| .IDEA | Adobe Ideas Document | 3.1 |
| .IDEA | IntelliJ IDEA Settings Directory | 3.5 |
| .IDEA | Tresor IDEA Encrypted File | 3.2 |
| .IDEPLUGIN | Xcode IDE Plug-in | 2.5 |
| .IDF | MIDI Instrument Definition File | 2.6 |
| .IDI | EVA Controller Event Log | 2.6 |
| .IDL | Interface Definition Language File | 3.6 |
| .IDLK | Adobe InDesign Lock File | 4.1 |
| .IDML | Adobe InDesign Markup Language File | 3.6 |
| .IDMS | Adobe InDesign Snippet | 3.7 |
| .IDPK | Adobe InDesign Package for GoLive File | 1.5 |
| .IDPP | Adobe InDesign Preflight Profile | 3.7 |
| .IDT | Windows Installer Database Text Archive File | 2.8 |
| .IDV | Inventor Design View | 3.7 |
| .IDW | Inventor Drawing | 3.3 |
| .IDX | VobSub Subtitles Index File | 3.6 |
| .IDX | Index File | 3.6 |
| .IDX | HMI Historical Log Index File | 3.2 |
| .IDX | Outlook Express Mailbox Index File | 3.1 |
| .IDX | Navigation POI File | 3.6 |
| .IDX0 | Runescape Cache Index File | 4.0 |
| .IDX255 | Runescape Cache File | 3.0 |
| .IEC | IEChooser HTML File | 1.0 |
| .IEPD | Information Exchange Package Documentation | 4.0 |
| .IES | IES Photometric Data File | 3.1 |
| .IF | Procedimientos-Uno IFWin Project File | 3.6 |
| .IFAITH | iFaith SHSH File | 2.3 |
| .IFC | Industry Foundation Classes File | 4.0 |
| .IFCXML | Industry Foundation Classes XML File | 3.0 |
| .IFCZIP | Compessed IFC File | 1.5 |
| .IFD | InForm Document | 4.0 |
| .IFF | Interchange File Format | 3.3 |
| .IFICTION | iFiction Metadata File | 2.5 |
| .IFL | 3ds Max Image File List | 3.5 |
| .IFM | Informed Form Data Document | 2.2 |
| .IFO | DVD-Video Disc Information File | 3.8 |
| .IFP | GTA Animation File | 4.4 |
| .IFP | InstallForge Project | 3.0 |
| .IFS | InfoSlips Package | 2.6 |
| .IFW | INTUS Firmware File | 3.0 |
| .IGB | Intrinsic Graphics Binary File | 2.7 |
| .IGC | International Gliding Commission Data File | 4.0 |
| .IGC | Anime List Builder Input File | 2.5 |
| .IGES | IGES Drawing | 3.4 |
| .IGG | SuiteProfiler Color Map File | 3.2 |
| .IGI | Indigo Image File | 3.9 |
| .IGM | Indigo Renderer Material File | 2.0 |
| .IGMA | INTUS Graph Mask Archive | 2.0 |
| .IGMESH | Indigo Renderer Mesh File | 2.0 |
| .IGN | RoboHelp Ignore List File | 2.7 |
| .IGP | Igor Published Music Notation File | 4.0 |
| .IGP | Intel Graphics Profile | 2.0 |
| .IGQ | Indigo Queue File | 3.5 |
| .IGR | Igor Engraver File | 3.3 |
| .IGR | Quest3D Channel Group Layout File | 3.0 |
| .IGS | IGES Drawing | 3.7 |
| .IGS | Indigo Renderer Scene File | 3.2 |
| .IGT | iGrafx Document Template | 1.3 |
| .IGX | iGrafx Document | 3.6 |
| .IGZ | Intrinsic Alchemy Asset | 2.0 |
| .IHW | IN-HEH Timeline Workspace | 4.0 |
| .IHX | IN-HEH Timeline Database | 3.3 |
| .II | IconWorkshop Extended Information File | 3.5 |
| .IIF | Intuit Interchange Format File | 3.7 |
| .IIL | CleanSweep Installation Log | 2.0 |
| .IIM | iMacro Macro File | 3.7 |
| .IIP | Install Creator Pro Project File | 4.0 |
| .IIP | ThinAnywhere Configuration File | 2.0 |
| .IIQ | Phase One RAW Image | 2.7 |
| .IIT | Install Creator Project File | 2.5 |
| .IIX | Translation Memory Index File | 4.0 |
| .IK | CryENGINE IK Animation File | 3.1 |
| .IKF | INTUS Keyboard File | 1.8 |
| .IKMP | IK Multimedia Preset FIle | 3.0 |
| .ILBM | Interleaved Bitmap Image | 3.3 |
| .ILDOC | QuickSilver Document | 3.5 |
| .ILG | InstallScript Log File | 3.0 |
| .ILK | Incremental Linking File | 3.4 |
| .ILO | I-LIVE-ON StoryTeller | 4.7 |
| .ILOGICVB | iLogic VB File | 4.0 |
| .IM | Indexed Mesh | 2.0 |
| .IM4M | IMG4 Manifest | 3.0 |
| .IM4P | IMG4 Payload File | 3.3 |
| .IMA | Sage ACT! Email Message | 3.0 |
| .IMA | Disk Image | 3.9 |
| .IMA | IMA ADPCM Audio | 1.0 |
| .IMAGE | Apple Disk Image | 3.1 |
| .IMAGE | Squeak Virtual Image | 3.0 |
| .IMAGE | OpenQwaq Image | 2.6 |
| .IMAGELIST | Where's My ... ? Image List | 2.5 |
| .IMAGEPORTFOLIOLIBRARY | Painter Image Portfolio Library | 2.2 |
| .IMAPMBOX | IMAP Mailbox | 3.0 |
| .IMAZING | iMazing iPhone Backup | 3.5 |
| .IMAZINGAPP | iMazing App Data Backup | 4.0 |
| .IMD | GIS Image Metadata File | 3.3 |
| .IMD | Microsoft VisioModeler File | 3.1 |
| .IMD | ImageDisk Disk Image File | 3.2 |
| .IME | Windows Input Method Editor File | 3.5 |
| .IMF | Id Music File | 2.6 |
| .IMF | Imago Orpheus Module | 1.0 |
| .IMG | Disc Image Data File | 4.0 |
| .IMG | Macintosh Disk Image | 3.5 |
| .IMG | ERDAS IMAGINE Image File | 3.0 |
| .IMG | Grand Theft Auto Data File | 3.4 |
| .IMG | Garmin Map File | 3.0 |
| .IMG | Floppy Disk Image | 3.6 |
| .IMG | GEM Image | 2.5 |
| .IMG2 | iPhone Firmware Image | 3.0 |
| .IMG3 | iPhone IMG3 File | 3.8 |
| .IMGA | Aleph One Image File | 3.0 |
| .IMI | Magellan Map File | 3.4 |
| .IMI | IncrediMail Image | 1.0 |
| .IMJ | JFIF Bitmap Image | 2.3 |
| .IML | IntelliJ IDEA Module | 3.7 |
| .IML | ACT! Internet Mail Message | 3.1 |
| .IMM | iMindMap Map File | 3.0 |
| .IMMODULES | GTK+ Module File | 3.7 |
| .IMOVIEEVENT | iMovie Event File | 4.0 |
| .IMOVIELIBRARY | iMovie Library File | 3.0 |
| .IMOVIEMOBILE | iOS iMovie Project | 2.9 |
| .IMOVIEPROJ | iMovie Project File | 2.9 |
| .IMOVIEPROJECT | iMovie Project | 2.5 |
| .IMOVIETRAILER | iOS iMovie Trailer | 4.0 |
| .IMP | Audition Impulse File | 2.8 |
| .IMP | Imagine Project | 3.3 |
| .IMP | Improv Spreadsheet | 3.1 |
| .IMPORT | Godot Engine Import Settings File | 3.5 |
| .IMR | Impromptu Report File | 4.3 |
| .IMT | My Time Data File | 3.7 |
| .IMTX | iMindMap Template File | 2.0 |
| .IMX | iMindMap Map File | 3.3 |
| .IMY | iMelody Ringtone File | 2.7 |
| .IMZ | WinImage Compressed Disk Image | 2.7 |
| .IN | Input File | 3.6 |
| .IN | Autoconf Input File | 4.3 |
| .IN | Spyware File | 2.2 |
| .INC | Include File | 3.6 |
| .INC | Total Commander Settings File | 2.5 |
| .INCA | InCopy CS3 Assignment File | 3.0 |
| .INCD | InCopy Document | 3.5 |
| .INCP | InCopy CS3 Package File | 2.0 |
| .INCT | InCopy Template | 2.0 |
| .INCX | InCopy CS3 Interchange File | 3.5 |
| .IND | Memory Stick Formatting File | 3.7 |
| .IND | Adobe InDesign Document | 3.5 |
| .INDB | Adobe InDesign Book File | 2.4 |
| .INDD | Adobe InDesign Document | 3.5 |
| .INDESIGNPLUGIN | Adobe InDesign Plug-in | 2.8 |
| .INDK | Adobe Shortcut Set File | 2.0 |
| .INDL | Adobe InDesign Library | 3.5 |
| .INDP | Adobe InDesign CS3 Package File | 2.0 |
| .INDS | Adobe InDesign Snippet File | 3.0 |
| .INDT | Adobe InDesign Template | 3.0 |
| .INETLOC | Internet Location | 4.0 |
| .INF | Setup Information File | 3.9 |
| .INF | Inform Source Code File | 4.0 |
| .INFINITEMACDISK | Infinite Mac Disk Image | 3.0 |
| .INFO | ZoomBrowser Image Index File | 3.5 |
| .INFO | Generic Information File | 4.1 |
| .INFO | Drupal Module Information File | 3.9 |
| .INFO | Minecraft Forge Information File | 4.0 |
| .INFO | Texinfo Document | 4.2 |
| .INFOPATHXML | Microsoft InfoPath Form | 3.7 |
| .INFORM | Inform Project | 2.5 |
| .INF_LOC | Windows Driver Information Cache File | 3.9 |
| .ING | MasterCook Ingredients File | 3.4 |
| .INI | Windows Initialization File | 3.8 |
| .INI | Gravis UltraSound Bank Setup File | 3.0 |
| .INI | Symbian OS Configuration File | 3.3 |
| .INI | Finale Preferences File | 3.0 |
| .INJB | InDesign Job Bag File | 2.4 |
| .INK | Mimio Notebook | 3.7 |
| .INK | Inker Image | 3.0 |
| .INK | Pantone Reference File | 2.5 |
| .INK | InkML Image | 3.5 |
| .INK | Pocket PC Handwritten Note | 2.8 |
| .INL | C++ Inline File | 3.3 |
| .INLK | Adobe InDesign Lock File | 4.0 |
| .INLX | Adobe InDesign Interchange Library | 2.0 |
| .INM | FaxMaster Document | 2.3 |
| .INMS | Adobe InDesign Menu Set File | 2.8 |
| .INO | Arduino Sketch | 4.2 |
| .INP | gretl Script File | 2.7 |
| .INP | Abaqus Input File | 3.4 |
| .INP | MAME Replay File | 3.3 |
| .INP | Sony Camcorder Image Management File | 3.8 |
| .INP | Urdu InPage Document | 3.8 |
| .INPROGRESS | Time Machine Backup Progress File | 3.7 |
| .INS | Internet Settings File | 3.6 |
| .INS | LaTeX Installer Script | 4.1 |
| .INS | Adlib Tracker Instrument File | 3.6 |
| .INS | Internet Naming Service File | 3.8 |
| .INS | Sample Cell II Instrument Definition File | 3.7 |
| .INS | Inspiration File | 3.5 |
| .INS | Ensoniq Instrument | 3.8 |
| .INS | AGT Game Instruction File | 2.9 |
| .INS | Internet Explorer Installation Settings | 1.0 |
| .INSP | Insta360 Panoramic Image | 3.2 |
| .INSTALLLOG | .NET Assembly Installation Log | 4.0 |
| .INSTALLSTATE | .NET Assembly Uninstaller File | 4.0 |
| .INSV | Insta360 Panoramic Video | 3.0 |
| .INT | SGI Integer Image | 3.3 |
| .INT | Sony Camcorder Image Management File | 3.5 |
| .INT | Unreal International Localization File | 3.5 |
| .INT | Fallout Compiled Script | 3.5 |
| .INT | Intellivision Game ROM File | 3.5 |
| .INTERNETCONNECT | Apple Internet Connect Document | 2.3 |
| .INV | INVedit File | 3.3 |
| .INV | Sphinx Object Inventory | 2.5 |
| .INV | Invivo Image | 2.0 |
| .INX | Adobe InDesign Interchange File | 4.0 |
| .INX | Compiled Script | 3.1 |
| .INX | Inkscape Extension Descriptor File | 4.0 |
| .IO | BrickLink Studio LEGO Model | 3.8 |
| .IOBIT | Advanced SystemCare Rollback File | 2.8 |
| .ION | File Description File | 4.0 |
| .IOPLIST | Mac OS X IOPLIST File | 4.2 |
| .IP | IconPackager Theme File | 3.8 |
| .IP | Interactive Physics Project | 2.0 |
| .IPA | iOS Application | 4.2 |
| .IPALIAS | iPhoto Alias File | 3.0 |
| .IPCC | iPhone Carrier Bundle | 3.7 |
| .IPCH | Intellisense Precompiled Header File | 3.4 |
| .IPD | BlackBerry Backup File | 3.9 |
| .IPF | SMS Installer Script | 2.5 |
| .IPF | iMPACT Project File | 3.0 |
| .IPF | Interchangeable Preservation File | 3.6 |
| .IPF | PCAN-Explorer Panel File | 2.0 |
| .IPF | OS/2 Help File | 3.7 |
| .IPG | iPod Game File | 2.9 |
| .IPHOTO | iPhoto Library File | 3.9 |
| .IPHOTOPROJECT | iPhoto Print Project | 1.0 |
| .IPICK | iPick Football Image | 4.0 |
| .IPJ | Inventor Project | 2.9 |
| .IPJ | ProFicient SPC Manufacturing Intelligence Project File | 3.0 |
| .IPK | Itsy Package | 3.3 |
| .IPK | webOS TV Application | 3.3 |
| .IPK | Interactive Package | 2.7 |
| .IPL | GTA Item Placement File | 3.9 |
| .IPLB | iPhoto Library Archive Document | 1.0 |
| .IPMETA | Apple iPhoto Metadata File | 3.0 |
| .IPN | Inventor Presentation | 3.0 |
| .IPOD | Rockbox Firmware File | 2.8 |
| .IPP | Inline Guard Macro File | 2.8 |
| .IPR | InstallShield Professional Project File | 3.8 |
| .IPR | IntelliJ IDEA Project File | 4.3 |
| .IPR | iProcrastinate Data File | 4.0 |
| .IPROJECT | iClone Project File | 4.0 |
| .IPS | Internal Patching System Patch File | 3.5 |
| .IPS | iOS Analytics Data | 4.0 |
| .IPS | PlayStation 2 In-Game Video | 1.0 |
| .IPSPOT | iPhoto Spot File | 3.3 |
| .IPSW | iPod and iPhone Software Update File | 4.3 |
| .IPT | Inventor Part | 3.3 |
| .IPTHEME | IconPackager Raw Theme File | 2.5 |
| .IPU | PlayStation 2 In-Game Video | 3.0 |
| .IPV | ibis Paint Artwork | 4.0 |
| .IPX | IPIX Image | 3.0 |
| .IPYNB | Jupyter Notebook | 3.6 |
| .IQ4 | IQ4E Controller Strategy File | 1.5 |
| .IQMOL | IQmol Archive | 3.3 |
| .IQP | IntelliQuilter Pattern | 2.0 |
| .IQY | Internet Query | 3.0 |
| .IR | Flipper Infrared Control File | 3.0 |
| .IRCAM | IRCAM Sound File | 3.0 |
| .IRCP | SpeedGrade IRIDAS Composite File | 3.5 |
| .IRF | CCTV DVR H.264 Video File | 3.1 |
| .IROCK | intelliRock Sensor Data File | 3.0 |
| .IROS | Adobe Save For Web Settings File | 2.0 |
| .IRP | InfraRecorder Project | 3.0 |
| .IRP | Internet Researcher Project File | 2.0 |
| .IRR | Irrlicht 3D Scene | 4.3 |
| .IRR | Brewer Lamp File | 1.5 |
| .IRRMESH | Irrlicht Static Mesh File | 4.0 |
| .IRS | Adobe Save For Web Settings | 4.3 |
| .IRX | Brewer Irradiation File | 4.0 |
| .IS1 | M3 Sakura Real-Time Save 1 File | 1.3 |
| .IS1 | Synergy/DE Data Index File | 1.0 |
| .IS2 | Thermal Image Data File | 3.3 |
| .ISA | Indie Studios Sound Archive | 2.7 |
| .ISALE | iSale Auction | 2.7 |
| .ISALETEMPLATE | iSale Template | 3.0 |
| .ISALLIC | iSale License File | 1.0 |
| .ISC | Xilinx Device Configuration File | 2.3 |
| .ISD | Flexera InstallShield Dialog Box File | 4.0 |
| .ISDATA | Icon Services Data | 3.0 |
| .ISE | InstallShield Express Project File | 3.9 |
| .ISE | Xilinx ISE Project | 2.3 |
| .ISF | Inspiration Flowchart Document | 2.9 |
| .ISF | Ink Serialized Format | 3.0 |
| .ISH | ISH Compressed Archive | 3.1 |
| .ISH1 | Animation-ish Wiggledoodle-ish Document | 4.0 |
| .ISH2 | Animation-ish FlipBook-ish Document | 3.0 |
| .ISH3 | Animation-ish Advanced-ish Document | 3.0 |
| .ISM | IIS Smooth Streaming Manifest File | 3.4 |
| .ISM | InstallShield Project File | 3.5 |
| .ISMA | IIS Smooth Streaming Audio File | 3.7 |
| .ISMC | Smooth Streaming Client Manifest File | 3.0 |
| .ISMCLIP | iStopMotion Animation Clip | 2.0 |
| .ISMV | IIS Smooth Streaming Video File | 3.5 |
| .ISN | Installer Source File | 4.2 |
| .ISO | Disk Image File | 4.2 |
| .ISO | Arbortext IsoDraw Document | 3.7 |
| .ISO | PlayStation 2 ROM File | 3.8 |
| .ISO | Wii / GameCube ROM | 3.3 |
| .ISO | PlayStation Portable ROM | 2.0 |
| .ISOZ | Compressed Arbortext IsoDraw Illustration | 3.7 |
| .ISP | IIS Internet Service Provider Settings | 4.2 |
| .ISPC | Image Surfer Pro Collection File | 2.5 |
| .ISPD | LabSolutions IR Data | 1.0 |
| .ISPX | iStudio Publisher Document | 2.5 |
| .ISR | GoMoku Game File | 4.3 |
| .ISS | InstallShield Silent Response File | 3.9 |
| .ISS | Inno Setup Script | 4.3 |
| .ISS | FunCom ISS Audio File | 4.0 |
| .IST | InstallShield Project Template File | 3.3 |
| .IST | Inspiration Template | 3.0 |
| .ISU | InstallShield Uninstaller Script | 3.8 |
| .ISX | SimulationX Project | 3.0 |
| .ISZ | Zipped ISO Disk Image | 3.6 |
| .IT | Impulse Tracker Module | 3.9 |
| .ITA | IconTweaker Theme Archive | 4.0 |
| .ITA | VTech InnoTab Application File | 3.0 |
| .ITC | iTunes Cover Flow Data File | 2.5 |
| .ITC2 | iTunes Cover Flow Data File 2 | 3.9 |
| .ITDB | iTunes Database File | 4.1 |
| .ITE | iTunes Extras File | 3.0 |
| .ITEMDATA-MS | Windows 8 Start Screen Item Data File | 3.9 |
| .ITF | Image Tuner File | 2.0 |
| .ITHMB | iPod and iPhone Photo Thumbnails File | 3.2 |
| .ITI | Impulse Tracker Instrument | 3.8 |
| .ITI | InterActual Skin File | 1.7 |
| .ITK | ScummVM Game Data File | 2.7 |
| .ITL | iTunes Library File | 3.5 |
| .ITLP | iTunes LP Album File | 4.0 |
| .ITLS | iTunes Live Stream URL | 4.0 |
| .ITM | iThink Model File | 1.7 |
| .ITMS | iTunes Music Store Link File | 3.3 |
| .ITMSP | iTunes Store Package | 2.7 |
| .ITN | TomTom Navigator Itinerary File | 2.3 |
| .ITPC | iTunes Podcast Link | 2.7 |
| .ITR | Icy Tower Replay File | 3.3 |
| .ITS | Internet Document Set | 2.0 |
| .ITS | Impulse Tracker Sample | 2.8 |
| .ITT | IconTweaker Theme File | 2.8 |
| .ITW | InTouch With Database | 4.1 |
| .ITX | FileNet eForms Designer Template | 3.0 |
| .IUP | Fritz Update File | 1.5 |
| .IUS | InfoTMIC Firmware Update File | 2.7 |
| .IV | Open Inventor Scene Graph File | 4.3 |
| .IV2I | Norton Ghost Incremental Virtual Volume Image | 4.5 |
| .IVA | Surveillance Video File | 3.6 |
| .IVA | Dementia.4207 Virus File | 1.5 |
| .IVC | InteliSea Vessel Configuration File | 1.5 |
| .IVD | Bitdefender Incremental Virus Definitions File | 2.0 |
| .IVE | OpenSceneGraph Binary File | 4.0 |
| .IVF | Indeo Video Format File | 3.0 |
| .IVR | Internet Video Recording | 3.8 |
| .IVR | Image Worlds File | 2.4 |
| .IVS | Initialization Vector File | 2.8 |
| .IVS | Internet Streaming Video | 2.3 |
| .IVT | Beyond 20/20 Table File | 1.5 |
| .IVT | International Volleyball 2006 Data File | 3.7 |
| .IVUE | Live Picture IVUE Image | 3.0 |
| .IW | Chain Engineering Database File | 2.0 |
| .IW | IdleWild Module | 2.5 |
| .IWA | iWork Archive File | 2.2 |
| .IWB | IWBasic Source Code File | 3.0 |
| .IWD | Call of Duty Game Data File | 4.0 |
| .IWDGT | iWeb Widget File | 2.0 |
| .IWI | Infinity Ward Texture File | 3.6 |
| .IWM | iWriteMusic Data File | 1.0 |
| .IWS | IntelliJ IDEA Web Page | 3.0 |
| .IWS | InstallWatch Scan File | 1.0 |
| .IWXDATA | iWorx Data File | 4.2 |
| .IWZ | InstallShield Express 2 Project File | 1.8 |
| .IX | dtSearch Index File | 3.0 |
| .IX2 | WordPerfect Address Book File | 3.0 |
| .IXA | Ulead Disc Image format | 3.0 |
| .IXB | Ulead Disc Image | 2.3 |
| .IZE | IZArc Archive | 3.0 |
| .IZZ | Isadora Media Control Project | 3.5 |
| .IZZY | Isadora Project | 3.5 |