File extensions start with character 'I'
| File Type | Category | File Format | |
|---|---|---|---|
| .i01 | Disk Image Files | DVD Shrink Part 2 File | |
| .i3pack | Audio Files | Point Blank Game Data File | |
| .i5z | Data Files | IUCLID 5 Import/Export File | |
| .iaf | Configuration Files | Outlook Internet Account File | |
| .iba | Data Files | iBooks Author Document | |
| .ibcd | Data Files | InstantBingoCard Document | |
| .ibooks | Data Files | Multi-Touch iBook | |
| .ica | Configuration Files | Citrix ICA File | |
| .icalevent | Data Files | iCal Event File | |
| .icaltodo | Data Files | iCal To Do File | |
| .icbu | Backup Files | iCal Backup File | |
| .ice | Compressed Files | ICE File Archive | |
| .icf | Backup Files | Zoom Router Configuration File | |
| .ichat | Data Files | iChat Saved Chat Log | |
| .icns | Apple System Files | Mac OS X Icon Resource File | |
| .ico | Icon Files | Icon File | |
| .ics | Multiple Use Files | iCalendar File | |
| .id2 | Data Files | Windows Live Messenger Emoticon File | |
| .idx | Multiple Use Files | Movie Subtitle File | |
| .ies | Data Files | IES Photometric Data File | |
| .ifaith | Data Files | iFaith SHSH File | |
| .ifc | 3D Graphics Files | Industry Foundation Classes File | |
| .iff | Amiga Files | Interchange File Format | |
| .ifo | Digital Video Files | DVD-Video Disc Information File | |
| .igc | Data Files | Anime List Builder Input File | |
| .igr | Layout Files | Igor Engraver File | |
| .igs | CAD Files | IGES Drawing File | |
| .ii | Data Files | IconWorkshop Extended Information File | |
| .iif | Data Files | Intuit Interchange Format File | |
| .iil | Text Files | CleanSweep Installation Log | |
| .iim | Program Execution Files | iMacro Macro File | |
| .image | Disk Image Files | Apple Disk Image | |
| .img | Disk Image Files | Macintosh Disk Image | |
| .img | Disk Image Files | Disc Image Data File | |
| .img3 | Apple System Files | iPhone IMG3 File | |
| .imi | Graphics Files | Magellan Map File | |
| .iml | Development Files | IntelliJ IDEA Module | |
| .imp | Audio Files | Audition Impulse File | |
| .imr | Data Files | Impromptu Report File | |
| .imt | Data Files | My Time Data File | |
| .imz | Disk Image Files | WinImage Compressed Disk Image | |
| .incp | Data Files | InCopy CS3 Package File | |
| .ind | Multiple Use Files | Memory Stick Formatting File | |
| .indd | Page Layout Files | Adobe InDesign Document | |
| .indt | Page Layout Files | Adobe InDesign Template | |
| .inetloc | Multiple Use Files | Internet Location | |
| .inf | Configuration Files | Setup Information File | |
| .inf_loc | Windows System Files | Windows Driver Information Cache File | |
| .info | Raster Graphics Files | ZoomBrowser Image Index File | |
| .ingr | Vector Graphics Files | Intergraph Image File | |
| .ini | Configuration Files | Windows Initialization File | |
| .ink | Vector Graphics Files | InkML Image | |
| .inp | Austodesk Files | Abaqus Input File | |
| .ins | Configuration Files | Internet Settings File | |
| .int | Vector Graphics Files | SGI Integer Image File | |
| .inv | Game Files | INVedit File | |
| .inx | Page Layout Files | Adobe InDesign Interchange File | |
| .inx | Data Files | Compiled Script | |
| .iobit | Multiple Use Files | Advanced SystemCare Rollback File | |
| .ip | Data Files | IconPackager Theme File | |
| .ipa | Program Execution Files | iOS Application | |
| .ipf | Executable Files | SMS Installer Script | |
| .ipg | Compressed Files | iPod Game File | |
| .ipk | Package Files | Itsy Package | |
| .ipmeta | Data Files | Apple iPhoto Metadata File | |
| .ipr | Development Files | InstallShield Professional Project File | |
| .iproject | Data Files | iClone Project File | |
| .ips | Binary Files | Internal Patching System Patch File | |
| .ipsw | Multiple Use Files | iPod and iPhone Software Update File | |
| .ipt | CAD Files | Inventor Part File | |
| .iqy | Microsoft Office Files | Internet Query | |
| .irf | Digital Video Files | CCTV DVR H.264 Video File | |
| .irock | Data Files | intelliRock Sensor Data File | |
| .irp | Data Files | Internet Researcher Project File | |
| .irr | Data Files | Brewer Lamp File | |
| .irx | Data Files | Brewer Irradiation File | |
| .is1 | Data Files | M3 Sakura Real-Time Save 1 File | |
| .isf | Data Files | Inspiration Flowchart Document | |
| .ish | Compressed Files | ISH Compressed Archive | |
| .ish1 | Data Files | Animation-ish Wiggledoodle-ish Document | |
| .ish2 | Data Files | Animation-ish FlipBook-ish Document | |
| .ish3 | Data Files | Animation-ish Advanced-ish Document | |
| .ismv | Digital Video Files | IIS Smooth Streaming Video File | |
| .isn | Multiple Use Files | Installer Source Files | |
| .iso | Disk Image Files | Disc Image File | |
| .ist | Development Files | InstallShield Project Template File | |
| .isz | Disk Image Files | Zipped ISO Disk Image | |
| .itc2 | Raster Graphics Files | iTunes Cover Flow Data File 2 | |
| .itdb | Database Files | iTunes Database File | |
| .ite | Data Files | iTunes Extras File | |
| .ithmb | Raster Graphics Files | iPod and iPhone Photo Thumbnails File | |
| .itl | Apple Files | iTunes Library File | |
| .itlp | Data Files | iTunes LP Album File | |
| .itm | Data Files | iThink Model File | |
| .itmsp | Data Files | iTunes Store Package | |
| .itn | Data Files | TomTom Navigator Itinerary File | |
| .itx | Data Files | ITX Form Template | |
| .iup | Data Files | Fritz Update File | |
| .ius | Android Files | InfoTMIC Firmware Update File | |
| .ivs | Data Files | Initialization Vector File | |
| .ivt | Data Files | Beyond 20/20 Table File | |
| .iw | Data Files | Chain Engineering Database File | |
| .iwd | Game Files | Call of Duty Game Data File | |
| .ix2 | Data Files | WordPerfect Address Book File | |
| .ixb | Data Files | Ulead Disc Image | |
| .ize | Encrypted Archive Files | IZArc Archive |