| Extension |
File Type |
File Description |
| .a | Developer | Static Library |
| .a00 | Compressed | ALZip Second Split Archive File |
| .a01 | Compressed | ALZip Third Split Archive File |
| .a02 | Compressed | ALZip Fourth Split Archive File |
| .a26 | Game | Atari 2600 ROM |
| .a2c | 3D Image | Alice Object File |
| .a2m | Settings | TS-AudioToMIDI Settings File |
| .a2m | Audio | AdLib Tracker 2 File |
| .a2theme | Settings | Aston 2 Theme File |
| .a2w | Developer | Alice World |
| .a3l | Data | Authorware 3 Library |
| .a3m | Data | Authorware 3 Macintosh File |
| .a3w | Data | Authorware 3 Windows File |
| .a4l | Data | Authorware 4 Library |
| .a4m | Data | Authorware 4 Macintosh File |
| .a4w | Data | Authorware 4 Windows File |
| .a52 | Game | Atari 5200 ROM |
| .a52 | Audio | Dolby Digital Audio File |
| .a5l | Data | Authorware 5 Library |
| .a5w | Web | Alpha Five Webpage File |
| .a5w | Data | Authorware 5 Windows File |
| .a65 | Data | Authorware 6.5 File |
| .a6p | Executable | Authorware 6 Program |
| .a8s | 3D Image | Anim8or Script |
| .aa | Audio | Audible Audio Book File |
| .aa | Disk Image | Generic CD Image |
| .aa3 | Audio | ATRAC Audio File |
| .aac | Audio | Advanced Audio Coding File |
| .aaf | Video | Advanced Authoring Format File |
| .aam | Data | Authorware Map File |
| .aao | Data | Agenda At Once File |
| .aao | Game | America's Army Map File |
| .aawdef | Misc | Ad-Aware Definitions File |
| .aax | Audio | Audible Enhanced Audiobook File |
| .ab | Developer | Applix Builder File |
| .ab | Backup | Android ADB Backup File |
| .ab | Data | DNA Sequence File |
| .ab | Audio | Ambling BookPlayer MP3 File |
| .ab1 | Data | DNA Electropherogram File |
| .ab2 | Data | Print Shop Address Book File |
| .ab3 | Data | PhotoImpact 3 Album File |
| .aba | Plugin | Avant Browser Add-on File |
| .aba | Backup | Palm Address Book Archive |
| .abbu | Backup | Address Book Backup |
| .abc | Developer | ActionScript Byte Code File |
| .abc | Vector Image | Micrografx ABC FlowCharter 6 File |
| .abc | Audio | ABC Music Notation |
| .abc | Developer | ABC Source File |
| .abcd | Data | AudioVisual Book Data File |
| .abdata | Data | Adobe Bridge Data File |
| .abf | Backup | Analysis Services Backup File |
| .abf | Font | Adobe Binary Screen Font File |
| .abi | Plugin | AbiWord Plug-in |
| .abi | Data | DNA Chromatogram File |
| .abk | Game | Arena Opening Book File |
| .abk | Game | Need for Speed Underground Audio File |
| .abk | Backup | Automatic Backup File |
| .abkprj | Data | Ashampoo Backup Project |
| .abm | Audio | Music Album |
| .abm | Raster Image | Photo Album |
| .abp | Data | AVS Barcode Profile |
| .abr | Misc | Adobe Photoshop Brushes File |
| .abw | Text | AbiWord Document |
| .aby | Data | AOL Address Book File |
| .ac | Executable | Autoconf Script |
| .ac$ | Misc | AutoCAD Temporary File |
| .ac3 | Audio | Audio Codec 3 File |
| .ac5 | Vector Image | ArtCut 5 Document |
| .ac6 | Vector Image | ArtCut 6 Document |
| .aca | Data | Agent Character Animation File |
| .acb | Misc | AOL Cab Launcher |
| .acb | Settings | Adobe Photoshop Color Book File |
| .acb | Settings | AutoCAD Color Book File |
| .acbl | Settings | Adobe Color Book Legacy File |
| .acc | Data | Graphics Accounts Data File |
| .accda | Plugin | Access Add-in File |
| .accdb | Database | Access 2007 Database File |
| .accdc | Database | Microsoft Access Signed Package |
| .accde | Database | Access Execute Only Database |
| .accdr | Database | Access Runtime Application |
| .accdt | Database | Microsoft Access Database Template |
| .accdw | Database | Microsoft Access Database Link File |
| .acd | Audio | ACID Project File |
| .acd | Developer | RSLogix 5000 Program |
| .acd-bak | Audio | Sony ACID Project Backup File |
| .acd-zip | Audio | Sony ACID Project With Embedded Media File |
| .ace | Compressed | WinAce Compressed File |
| .acf | Data | Agent Character Data File |
| .acf | Game | Steam Application Cache File |
| .acf | Settings | Adobe Photoshop Custom Filter File |
| .acfm | Font | Adobe Composite Font Metrics File |
| .acg | Data | Agent Preview File |
| .acl | Misc | AutoCorrect List File |
| .acm | Audio | Interplay Audio File |
| .aco | Settings | Adobe Photoshop Color Swatch File |
| .acp | Developer | EditPlus Auto-Completion File |
| .acp | Backup | Alfresco Content Package |
| .acp | Audio | aacPlus Audio File |
| .acr | Backup | Acer eRecovery Management Backup File |
| .acr | Executable | ACRobot Script |
| .acr | Raster Image | American College of Radiology File |
| .acrobatsecuritysettings | Settings | Adobe Acrobat Security Settings File |
| .acrodata | Settings | Acrobat Data File |
| .acroplugin | Plugin | Adobe Acrobat Plug-in |
| .acs | Misc | Agent Character File |
| .acsm | Misc | Adobe Content Server Message File |
| .act | Text | FoxPro Documenting Wizard Action Diagram |
| .act | 3D Image | Genesis3D Actor File |
| .act | Audio | ADPCM Compressed Audio File |
| .act | Settings | Adobe Color Table File |
| .act | Developer | DS Game Maker Action File |
| .action | Executable | Automator Action |
| .actm | Executable | AutoCAD Action Macro File |
| .actx | Developer | DS Game Maker Action Description File |
| .acv | Settings | Photoshop Curves File |
| .acw | Settings | Windows Accessibility Wizard File |
| .acx | Game | Atari ST Program |
| .ad | Misc | After Dark Screensaver |
| .ada | Developer | Ada Source Code |
| .adb | Database | Ability Database File |
| .adb | Developer | Ada Body File |
| .adb | Database | Alpha Five Database File |
| .adc | Raster Image | Scanstudio 16 Color Image |
| .add | Misc | Dynamics AX Developer Documentation File |
| .addin | Developer | Visual Studio Add-in Definition File |
| .addon | Plugin | CFS Console Add-on File |
| .ade | Database | Access Project Extension |
| .adf | Database | ACT! Data File |
| .adf | Disk Image | Amiga Disk File |
| .adg | Audio | Ableton Device Group |
| .adi | Backup | Active@ Disk Image Backup File |
| .adi | Misc | Dynamics AX Developer Documentation Index File |
| .adi | CAD | AutoCAD Device-Independent Binary Plotter File |
| .adm | System | Administrative Template File |
| .adm | Misc | Portfolio Admin-Level Access Flag |
| .adml | System | Group Policy Language-Specific Administrative Template |
| .admx | System | Group Policy Administrative Template File |
| .ado | Settings | Adobe Photoshop Duotone Options File |
| .adp | Database | Access Project |
| .adr | Web | Opera Bookmarks File |
| .ads | Developer | Ada Specification File |
| .adt | CAD | AutoCAD Audit Log |
| .adt | Game | World of Warcraft Map File |
| .adt | Audio | ADTS Audio File |
| .adt | Data | ACT! Document Template |
| .adts | Audio | Audio Data Transport Stream File |
| .adu | Data | Addict User Dictionary File |
| .adv | Audio | Ableton Device Preset File |
| .adx | Data | Approach Index File |
| .adz | Disk Image | Compressed Amiga Disk File |
| .aea | Backup | AdWords Editor Archive |
| .aea | Settings | Ae Timer Alarm Document |
| .aep | Developer | Activ E-Book Project |
| .aep | Video | After Effects Project |
| .aepx | Video | After Effects XML Project |
| .aet | Video | After Effects Project Template |
| .aetx | Video | After Effects XML Project Template |
| .aex | Web | Alpha Five Compiled Global Functions File |
| .af2 | Vector Image | Micrografx ABC FlowCharter 2 File |
| .af3 | Vector Image | Micrografx ABC FlowCharter 3/4 File |
| .afc | Audio | Mass Effect 2 Audio File |
| .afd | Disk Image | AFF Disk Image Part File |
| .afd | CAD | Alphacam Flame Drawing |
| .afe | Data | Avid File Exchange File |
| .aff | Disk Image | AFF Disk Image |
| .afm | Font | Adobe Font Metrics File |
| .afm | Disk Image | AFF Metadata File |
| .afp | Encoded | FileProtector Encrypted File |
| .afp | Page Layout | Advanced Function Presentation File |
| .afploc | Misc | Apple Filing Protocol Location |
| .afs | CAD | STAAD.foundation Project File |
| .aft | Data | Ancestry.com Family Tree Database |
| .afx | Raster Image | Auto FX Photo/Graphic Edges Image |
| .agd | Data | AgileGraph Data File |
| .agd | Misc | Agile Advantage E-mail Attachment |
| .age3scn | Game | Age of Empires 3 Scenario File |
| .aggr | Data | Adobe Captivate Aggregate File |
| .agi | Developer | Asterisk Gateway Interface File |
| .agif | Raster Image | Active GIF Creator Project |
| .agm | Audio | DTS Multi-channel Pro Packer File |
| .agp | Raster Image | ArtGem Project File |
| .ahd | Misc | Dynamics AX Online Help Data File |
| .ahi | Misc | Dynamics AX Online Help Index File |
| .ahk | Executable | AutoHotkey Script |
| .ahl | Settings | eMule Metadata File |
| .ahs | Settings | Adobe Halftone Screen File |
| .ahu | Settings | Adobe Photoshop HSL File |
| .ahx | Audio | WinAHX Tracker Module |
| .ai | Game | Battlefield 2 Artificial Intelligence File |
| .ai | Vector Image | Adobe Illustrator File |
| .aia | Settings | Adobe Illustrator Action File |
| .aic | Raster Image | Advanced Image Coding File |
| .aif | Audio | Audio Interchange File Format |
| .aif | Misc | Symbian Application Information File |
| .aifb | Data | AIF Builder Project File |
| .aifc | Audio | Compressed Audio Interchange File |
| .aiff | Audio | Audio Interchange File Format |
| .aim | Text | AIMMS ASCII Model File |
| .aim | Misc | AOL Instant Messenger Launch File |
| .ain | Game | Source Engine Compiled AI Nodegraph File |
| .ain | Compressed | AIN Compressed File Archive |
| .aip | Plugin | Illustrator Plug-in |
| .air | Game | M.U.G.E.N. Animation File |
| .air | Executable | Adobe AIR Installation Package |
| .ais | Audio | Velvet Studio Instrument |
| .ais | Raster Image | ACDSee Image Sequence File |
| .ait | Settings | Adobe Illustrator Template |
| .aiv | Data | AIVault Data File |
| .ajp | Video | CCTV Video File |
| .akp | Audio | Akai Sampler File |
| .al | Audio | A-Law Compressed Sound Format |
| .alac | Audio | ALAC Encoded Audio File |
| .alaw | Audio | A-Law Compressed Sound Format |
| .alb | Developer | Alpha Five Library |
| .albm | Raster Image | HP Photo Printing Software Album File |
| .alc | Audio | Ableton Live Clip File |
| .alc | Data | Dynamics AX Label Description File |
| .ald | Data | Dynamics AX Application Label Data File |
| .ale | Video | Avid Log Exchange File |
| .alf | Database | ACT! Lookup File |
| .ali | Data | Dynamics AX Label Index File |
| .all | Settings | Java RMI Policy File |
| .all | Audio | Cubasis Project File |
| .alp | Plugin | Ableton Live Pack File |
| .alr | Game | ADRIFT Language Resource File |
| .als | Audio | Ableton Live Set File |
| .alt | Misc | Dynamics AX Temporary File |
| .alv | Settings | Adobe Photoshop Levels File |
| .alx | Web | ActiveX Layout Control File |
| .alx | Settings | BlackBerry Application Loader XML File |
| .alz | Compressed | ALZip Archive |
| .am | Developer | Automake Makefile Template |
| .am1 | Game | Adventure Maker |
| .am4 | Developer | AutoPlay Media Studio 4 Project File |
| .am5 | Developer | AutoPlay Media Studio 5 Project File |
| .am6 | Developer | AutoPlay Media Studio 6 Project |
| .am7 | Developer | AutoPlay Media Studio 7 Project |
| .amb | Data | AIMMS Model File |
| .amf | Audio | Advanced Module File |
| .amfm | Font | Adobe Multiple Font Metrics File |
| .aml | Misc | Microsoft Assistance Markup Language File |
| .amp | Settings | Adobe Photoshop Curves Map File |
| .amr | Audio | Adaptive Multi-Rate Codec File |
| .ams | Audio | Velvet Studio Module |
| .ams | Audio | Extreme Tracker Module |
| .ams | Settings | Adobe Monitor Setup file |
| .amsorm | Data | OnLine Ringman Auction Client File |
| .amu | Data | PictureGear Studio Photo Album File |
| .amv | Video | Anime Music Video File |
| .amx | Plugin | AMX Mod Plugin File |
| .amx | Video | Adobe Motion Exchange File |
| .amxd | Audio | Ableton Max Patch File |
| .amxx | Plugin | AMX Mod X Plugin File |
| .amz | Music | Amazon MP3 Downloader File |
| .an1 | Data | Street Atlas USA Draw File |
| .an2 | Game | Croc Legend of the Gobbos Animation File |
| .an8 | 3D Image | Anim8or File |
| .ani | System | Windows Animated Cursor |
| .anim | 3D Image | Antibody Animation File |
| .anim | Video | Amiga Animation File |
| .anim | 3D Image | Maya Animation File |
| .anim | 3D Image | Unity Animation File |
| .animset | 3D Image | FaceFX Animation Set File |
| .animset_ingame | 3D Image | FaceFX In-Game Animation Set File |
| .anjuta | Developer | Anjuta IDE Project File |
| .anm | 3D Image | 3D Animation File |
| .anme | Data | Anime Studio Document |
| .ann | System | Help Annotations |
| .annot | Misc | Adobe Digital Editions Annotations File |
| .ans | Data | HotDocs Binary Answer File |
| .ans | Text | ANSI Text File |
| .anx | Data | HotDocs Answer File |
| .any | CAD | AnyRail Layout Plan |
| .aob | Audio | DVD-Audio Audio Object File |
| .aod | Misc | Dynamics AX Object Data File |
| .aoi | Misc | Dynamics AX Application Object Index File |
| .aois | Settings | CFS Console Add-on Installer Settings File |
| .aol | Misc | America Online File |
| .aos | System | ARCHOS PCtablet Firmware File |
| .ap | Web | Active Page |
| .apa | Developer | RSView Development Project Archive |
| .apd | Plugin | Eclipse Plugin Descriptor File |
| .apd | Raster Image | ACDSee Photo Document |
| .ape | Audio | Monkey's Audio Lossless Audio File |
| .ape | Plugin | AVS Plugin Effects File |
| .apf | Misc | Adobe Profile File |
| .apf | Audio | Sony Ericsson Firmware Acoustics File |
| .aph | Data | Ability Album File |
| .api | Settings | Adobe Photoshop Inks File |
| .api | Plugin | Acrobat Plug-in |
| .apk | Executable | Android Package File |
| .apl | GIS | ArcPad Layer File |
| .apl | Audio | Monkey's Audio Track Information File |
| .apl | Plugin | ACDSee Plugin File |
| .apm | Raster Image | Aldus Placeable Metafile Image |
| .apng | Raster Image | Animated Portable Network Graphic |
| .apnx | Misc | Amazon Page Number Index File |
| .app | Executable | Symbian OS Application |
| .app | Executable | FoxPro Generated Application |
| .app | Executable | Mac OS X Application |
| .applescript | Executable | AppleScript File |
| .application | Settings | ClickOnce Deployment Manifest File |
| .appref-ms | Settings | Microsoft Application Reference File |
| .apr | GIS | ArcView Project File |
| .apr | Developer | Apadana Project File |
| .aps | Raster Image | Greeting Card Studio Project File |
| .aps | Developer | Visual C++ Resource File |
| .apx | Raster Image | Ability Photopaint Studio Image |
| .apz | Compressed | Autoplay Media Studio Exported Project |
| .ar | Compressed | Unix Static Library |
| .ar | Game | Midtown Madness Data File |
| .arc | Backup | Symbian OS Backup File |
| .arc | Game | African Safari Data File |
| .arc | Compressed | Compressed File Archive |
| .arc | Backup | Norton Backup Archive |
| .arc | Data | Nintendo Archive File |
| .arch00 | Game | F.E.A.R. Game Archive |
| .ard | CAD | ArtiosCAD Workspace File |
| .arena | Game | Quake 3 Engine Arena File |
| .arf | Video | WebEx Advanced Recording File |
| .arg | Settings | AutoCAD Profile |
| .arh | Data | ArheoStratigraf Project File |
| .arh | Compressed | ProTool Compressed Project File |
| .ari | Compressed | ARI Compressed File Archive |
| .aria | Audio | Chipsounds Sound File |
| .ariax | Audio | Chipsounds XML Sound File |
| .arj | Compressed | ARJ Compressed File Archive |
| .ark | Compressed | PowerDesk Pro Archive |
| .arl | Settings | AOL Organizer File |
| .aro | Web | SteelArrow Web Application File |
| .arp | Settings | Advanced RAR Password Recovery Setup |
| .arpack | Plugin | ArtRage Package |
| .arr | Raster Image | Amber Graphic File |
| .arr | Misc | Advanced RAR Password Recovery Project |
| .arsc | Developer | Android Package Resource File |
| .arscript | Executable | ArtRage Script |
| .art | Raster Image | AOL Compressed Image File |
| .art | Developer | Artifacts Artifact File |
| .art | Vector Image | Art Document |
| .artproj | Developer | Artifacts Project |
| .artwork | Raster Image | ArtStudio Image |
| .arw | Raster Image | ArtStudio Image |
| .arw | Raster Image | Sony Digital Camera Image |
| .arx | Plugin | AutoCAD Runtime Extension File |
| .as | Developer | ActionScript File |
| .as | Data | AppleSingle File |
| .as2proj | Developer | FlashDevelop ActionScript 2 Project File |
| .as3proj | Developer | FlashDevelop ActionScript 3 Project File |
| .as4 | Backup | askSam Backup File |
| .asa | Web | ASP Configuration File |
| .asat | 3D Image | Assemble SAT 3D Model File |
| .asax | Web | ASP.NET Server Application File |
| .asb | Executable | Alphacam Stone VB Macro File |
| .asc | Developer | ActionScript Communication File |
| .asc | Encoded | PGP ASCII Armored File |
| .asc | Text | Autodesk ASCII Export File |
| .asc | Text | ASCII Text File |
| .asc | CAD | LTspice Circuit Schematic File |
| .ascii | Text | ASCII Text File |
| .ascx | Web | ASP.NET User Control File |
| .asd | Audio | Ableton Live Sample Analysis File |
| .asd | Backup | Word AutoSave File |
| .ase | Text | Autodesk ASCII Scene Export File |
| .ase | Audio | Velvet Studio Sample |
| .ase | Settings | Adobe Swatch Exchange File |
| .asec | System | Android Secure Application File |
| .asf | Video | Advanced Systems Format File |
| .ash | Game | Audiosurf Audio Metadata File |
| .ash | Game | KoLmafia ASH Script |
| .ash | Misc | Nintendo Wii System Menu File |
| .ashbak | Backup | Ashampoo Backup Archive |
| .ashdisc | Disk Image | Ashampoo Burning Studio Image |
| .ashprj | Data | Ashampoo Burning Studio Project |
| .ashx | Web | ASP.NET Web Handler File |
| .asi | Developer | Alpha Five Variable File |
| .ask | Database | askSam Database |
| .asl | Settings | Photoshop Style |
| .asm | Developer | Assembly Language Source Code File |
| .asm | CAD | Solid Edge Assembly File |
| .asm | Developer | Visual Studio Assembler Source Code File |
| .asm | Data | Pro/ENGINEER Assembly File |
| .asmx | Web | ASP.NET Web Service File |
| .asnd | Data | Adobe Sound Document |
| .asp | Web | Active Server Page |
| .aspx | Web | Active Server Page Extended File |
| .asr | Data | Adobe Photoshop Scratch File |
| .asr | Web | ActionScript Remote Document |
| .ass | Misc | Aegisub Advanced Substation Alpha File |
| .asset | Game | Unity Asset File |
| .ast | Data | ClarisWorks Assistant File |
| .ast | Spreadsheet | Ability Spreadsheet Template |
| .ast | Settings | Adobe Color Separations Table |
| .asv | Settings | Adobe Photoshop Selective Color File |
| .asw | Raster Image | ACDSee Slideshow Wizard File |
| .aswcs | Settings | Avast! Compressed Skin File |
| .asws | Settings | Avast! Skin File |
| .asx | Video | Microsoft ASF Redirector File |
| .asy | Vector Image | Asymptote Module |
| .asy | CAD | LTspice Symbol File |
| .at3 | Audio | ATRAC3 Audio File |
| .at5 | GIS | Lowrance Map File |
| .atc | Settings | AutoCAD Tool Catalog File |
| .ate | Backup | Office Accounting Compressed Backup File |
| .atf | Data | Axon Text File |
| .atf | Settings | Photoshop Transfer Function File |
| .ath | Settings | Alienware AlienFX Theme File |
| .ati | Backup | Office Accounting Updated Company File |
| .atm | 3D Image | Vue Atmospheres File |
| .atm | Game | PSP Game Audio File |
| .atn | Settings | Photoshop Actions File |
| .atom | Web | Atom Syndication Format |
| .atr | Disk Image | Atari Disk Image |
| .atrac | Audio | Sony ATRAC Audio File |
| .ats | Data | Advanced ETL Transformation Script |
| .att | Web | Web Form Post Data File |
| .att | CAD | Alphacam Lathe Tool File |
| .atx | Plugin | Animation Master Plugin File |
| .aty | Text | Association Type Placeholder |
| .atz | Misc | Atomic Time Zone File |
| .atz | Settings | Aston Compiled Theme |
| .au | Audio | Audio File |
| .au3 | Developer | AutoIt v3 Script |
| .aud | Audio | Video Game Compressed Audio File |
| .aup | Audio | Audacity Project File |
| .aut | Developer | AutoIt Script File |
| .automaticdestinations-ms | System | Windows Jump List File |
| .autoplay | Developer | AutoPlay Media Studio Project File |
| .aux | GIS | Auxiliary File |
| .aux | Settings | LaTeX Auxiliary File |
| .auz | Misc | Ableton Authorization File |
| .avastlic | Misc | Avast! License File |
| .avatar | Raster Image | Google Talk Avatar File |
| .avb | Video | Avid Bin File |
| .avc | Data | Kaspersky Virus Database |
| .avd | Video | Movie Edit Pro Video Information File |
| .ave | Settings | Avid User File |
| .avenirproj | Data | StoryMill Project |
| .avery | Page Layout | Avery Design & Print Online Label File |
| .avgdx | Misc | AVG Diagnostics File |
| .avi | Video | Audio Video Interleave File |
| .avj | Data | AntiVir Job File |
| .avl | Data | AntiVir Status Report File |
| .avl | GIS | ArcView Legend File |
| .avp | Video | Avid Project File |
| .avp | Data | AntiVir Profile |
| .avr | Audio | Audio Visual Research File |
| .avs | Settings | AVS Preset File |
| .avs | Settings | Adobe Photoshop Variations File |
| .avs | Settings | Avid Project Preferences File |
| .avs | Video | AviSynth Script File |
| .avs | Video | Application Visualization System File |
| .avx | Plugin | ArcView Extension File |
| .avx | Plugin | Avid Plugin File |
| .aw | Data | Answer Wizard File |
| .awb | Audio | AMR-WB Audio File |
| .awc | Misc | Emulex AWC Firmware Update File |
| .awcav | Settings | ActiveWorlds Custom Avatar File |
| .awd | Raster Image | Artweaver Document |
| .awd | Misc | Award BIOS Update File |
| .awd | Raster Image | Microsoft Fax Document |
| .awdb | Data | Access Walker Database File |
| .awg | Vector Image | Ability Draw Document |
| .awg | Data | Activeworlds Object Group File |
| .awk | Developer | AWK Script |
| .awkw | Misc | Awkwords Word Generator File |
| .awm | Web | AllWebMenus Project File |
| .awp | Text | Ability Write Template |
| .aws | Spreadsheet | Ability Spreadsheet File |
| .aws | Settings | AutoCAD Work Space File |
| .awt | Text | AbiWord Template |
| .aww | Text | Ability Write Document |
| .ax | Plugin | DirectShow Filter |
| .axd | Web | ASP.NET Web Handler File |
| .axe | GIS | AutoRoute Map File |
| .axe | Developer | Annotated XML Example File |
| .axm | Video | AXMEDIS Object |
| .axp | Settings | CDBurnerXP Audio Compilation File |
| .axt | Settings | Adobe Photoshop Extract File |
| .axx | Encoded | AxCrypt Encrypted File |
| .ay | Audio | AY Chiptune File |
| .azw | Data | Amazon Kindle eBook File |
| .azw1 | Data | Amazon Topaz eBook |
| .azz | Data | AZZ Cardfile Database File |
