#_A_EXTENSIONS

.A    ADA program file (ADA programming language).
.A    Addendum file (Documents/Texts).
.A    Archive file (KetilO's FbEdit FreeBASIC Editor).
.A    Archive file (Many applications).
.A    ASCII text document file (Many applications).
.A    Backup file.
.A00 .A99 Multi-volume ARJ archive file (Many applications).
.A11  AIIM monochrome/grayscale graphics file (Many image applications).
.A31  Macromedia Authorware 3 library file (Macromedia Authorware 3).
.A3D  Amapi 3D model project file (Amapi 3D).
.A3K  A3000 digital audio sample file (Yamaha A3000).
.A3L  Macromedia Authorware 3 Library file (Macromedia Authorware 3).
.A3M  Macromedia Authorware 3 for Macintosh file (Macromedia Authorware 3 Macintosh operating system).
.A3W  Macromedia Authorware 3 for Windows file (Macromedia Authorware 3 for Windows operating system).
.A41  Macromedia Authorware 4 Library file (Macromedia Authorware 4).
.A4L  Macromedia Authorware 4 Library file (Macromedia Authorware 4).
.A4M  Macromedia Authorware 4 Module for Macintosh file (Macromedia Authorware 4 Macintosh operating system).
.A4P  Macromedia Authorware 4 Program file(Macromedia Authorware 4).
.A4W  Macromedia Authorware 4 Module for Windows file (Macromedia Authorware 4 Windows operating system).
.A51  Macromedia Authorware 5 Library file (Macromedia Authorware 5).
.A5L  Macromedia Authorware 5 Library file (Macromedia Authorware 5).
.A64  Artist 64 image format file.
.A64  Commodore 64 SID audio file (SIDplay32).
.A6D  Authorware 6 model file (Macromedia Authorware 6).
.A6E  Authorware 6 External library file (Macromedia Authorware 6).
.A6L  Authorware 6 Library file (Macromedia Authorware 6).
.A6P  Authorware 6 Project file (Macromedia Authorware 6).
.A6R  Authorware 6 Runtime file (Macromedia Authorware 6).
.A8   24bit 3D animation file (Cubicomp PictureMaker).
.A86  Intel x86 Assembler source code file.
.A98  AGFA ProSet 9800 printer support file.
.AA   ASCII or ANSI Art file. Drawings or animation composed entirely of text. ANSI requires ANSI-capable reader or device/hardware (Terminal programs, e-readers, etc).
.AA   Audio book file.
.AA   Automated Analyst document file (PROGNOSIS Automated Analyst).
.AAA  AppCam Automation file (AppCam).
.AAA  Backup file.
.AAA  Softphrase Automation file.
.AAA  Temporary file.
.AAB  Authorware Binary file (Macromedia Authorware).
.AAC  AAC audio file (Media players and other audio applications).
.AAC  Advanced Audio Coding format audio file (Many applications).
.AAC  Advanced Audio Coding format audio stream file (many applications).
.AAM  Authorware Map file (Macromedia Authorware).
.AAO  America's Army game map Overview file (America's Army).
.AAP  Apollo Advanced playlist file.
.AAS  Authorware Segment file (Macromedia Authorware).
.AB   Applix Builder data file (Applix Builder).
.AB$  AutoCAD plot file (Autodesk's AutoCAD).
.AB2  Address Book file (Parson's Address Book 2).
.AB3  Album file V3 file (Ulead PhotoImpact 3 Album).
.AB6  AB Stat 6 data file.
.AB8  AB Stat 8 data file.
.ABA  Address Book file (Palm operating system applications and Palm OS emulators).
.ABC  ABC Flowcharter image file (ABC Flowcharter).
.ABC  Musical Notation language file.
.ABC  PageABC Web Document/Template file = HTML markup (Bridgewell/ABCHood.com PageABC).
.ABE  ABE control file (Mozilla Firefox).
.ABF  Adobe Binary screen Font file (Adobe Systems' applications).
.ABI  ARM binary/executable file (Android cellphones and other ARM microprocessor driven devices).
.ABICOLLAB AbiWord Collaboration document file (AbiSource AbiWord).
.ABK  Address Book database 1.0 file (MindScape PrintMaster Gold).
.ABK  Address Book database file (MindScape PrintMaster).
.ABK  Automated Backup file (Many applications).
.ABKBAK Ashampoo Backup file (Ashampoo's Burning Studio).
.ABKPRJ Ashampoo Backup Project file (Ashampoo Burning Studio).
.ABM  Album file (Many applications).
.ABM  Album file (Ulead PhotoImpact Album).
.ABO  Applix Builder file (Applix Builder).
.ABR  Adobe Photoshop Brushes file (Adobe Photoshop and other image editors).
.ABS  Abstract file.
.ABW  Uncompressed AbiWord format document file (AbiSource AbiWord). ABW.GZ=GZip compressed, .ZABW=ZIP compressed.
.ABX  Address Book file (Corel WordPerfect 8).
.AC$  AutoCAD temporary/undo file (Autodesk AutoCAD).
.AC3  AC3 audio format file = A/52 audio format file (Many media applications).
.AC3  Dolby Digital AC3 format audio file (many applications).
.ACA  Microsoft Agent character file (Microsoft Windows).
.ACA  Project Manager workbench file in HTTP format (Microsoft Windows).
.ACB  ACBM Bitmap image file (Image editors).
.ACB  Application/installer Cabinet file (America Online CDs).
.ACC  Viewmax file (Dr-DOS).
.ACCDB Access Database file (Microsoft Access 2007 and other database applications).
.ACCESS Java Runtime Environment (JRE) Remote JMX API access control file (Plaintext).
.ACCESS Remote Access control file - contains name and pass of administrator (VideoLAN Team's VideoLAN Client/VLC).
.ACD  ACDSee file (ACD Systems' ACDSee).
.ACD  Acid music data file (Sonic Foundry Acid).
.ACD  allCLEAR Drawing file (allCLEAR).
.ACD  allCLEAR Flowcharting Data file (allCLEAR).
.ACD  Channel Data file (Chromeleon).
.ACD  Agent Character Definiton data file (Microsoft Windows Agent).
.ACE  ACE DXT1 texture file (Martin Wright's DXTBmp Editor).
.ACE  ACE format archive container file (Marcel Lemke's WinACE and other archiving applications).
.ACE  Aces200 image file (Many image applications).
.ACF  Adobe Photoshop Custom Filter file (Adobe Photoshop).
.ACF  Advice Calculator database file (BM Software Advice Calculator).
.ACF  Agent Character File in HTTP format (Microsoft Agent).
.ACF  Application configuration file (TMPGEnc MPEG video encoder).
.ACG  Agent Graphics preview file (Microsoft Windows Agent).
.ACH  System snapshot file (Speccy).
.ACL  AutoCorrection List file (Microsoft Office).
.ACM  ACBM bitmap image file.
.ACM  Audio Compression Manager codec file (Microsoft Windows).
.ACM  Compressed audio file (Interplay).
.ACO  Adobe Color swatches file (Adobe Photoshop/Photo Elements).
.ACO  ArtWeaver Color set file (Boris Eyrich Software Artweaver).
.ACR  American College of Radiology image format file (Many image applications).
.ACR  Dicom image file (Many image applications).
.ACRODATA Acrobat user Data store file (Adobe Acrobat).
.ACS  Microsoft Agent Character file (Microsoft Windows).
.ACS2 Skin package v2 file (AIMP media player).
.ACS3 Skin package v3 file (AIMP media player).
.ACSRF Audition Control Surface plug-in file (Adobe Systems' Audition).
.ACT  Access Codes for font file (Microsoft Windows).
.ACT  Adobe Color Table/palette file (Adobe Systems' Photoshop and other image editors).
.ACV  Adobe Photoshop Curves file (Adobe Photoshop).
.ACW  Accessibility Wizard configuration file (Microsoft Windows).
.ACX  File description file (FOCUS/WebFOCUS).
.AD   Advertisement file = JPEG or GIF image.
.AD   Ascend password protocol file (Ascend).
.AD   Screensaver application file (Berkeley Systems After Dark Deluxe 4).
.ADA  ActiveDocs Answer set file.
.ADA  ADA program file (ADA programming language).
.ADA  Adaptation file (eMagic SoundDiver).
.ADB  Account Database file (CIX's Ameol2).
.ADB  ADA package Body file (ADA programming language).
.ADB  ADA programming language batch file (Many applications).
.ADB  Address Book file (Corel's Word Perfect Office).
.ADB  AddWeb Database file (CyberspaceHQ's Addweb).
.ADB  Appointment Database file (HP Organizers).
.ADC  Analog to Digital Conversion speech control file.
.ADC  Demo Container file (Chromeleon).
.ADCF Audio Dedupe Cache File (MindGems' Audio Dedupe).
.ADD  Address file (Adobe Systems' Pagemaker).
.ADD  Advantage Database Server Dictionary file.
.ADDON Addon configuration file (WinZIP).
.ADE  Access Database project Extension file (Microsoft Access 2002).
.ADF  Amiga Disk Format disk image file (Commodore Amiga operating system).
.ADF  Amiga Disk Format image file (Amiga Forever Amiga operating system emulator).
.ADF  Auction Designer workspace data File (Auction Designer 3).
.APD  Aml Pages documents List file (Mazov Gosha's Aml Pages notes manager).
.ADM  Administrative policy template file (Microsoft Windows).
.ADM  After Dark screensaver Module file (After Dark).
.ADN  Access New/blank Document template file (Microsoft Access 2002).
.ADN  Add-in file (Lotus 1-2-3).
.ADN  Add-on file (CIX's Ameol2).
.ADO  Adobe Duotone Options file (Adobe Photoshop).
.ADP  Access Database Project file (Microsoft Access).
.ADP  AOLserver Dynamic Page file (America OnLine).
.ADPF Audio Dedupe Project File (MindGems' Audio Dedupe).
.ADR  Address Book file (Many applications).
.ADR  Address book file (Smart Address).
.ADR  Address Plus Database file (AddressPlus).
.ADR  Addresses/bookmarks file (Opera web browser).
.ADR  After Dark Random screensaver module file.
.ADR  AntiDupl saved Results file (Yermalayeu Ihar AntiDupl.NET).
.ADS  ADA package Specification file.
.ADS  ADA programming language script file (Many applications).
.ADSITES Ad/Adserver database file (Deerfield Communications' InterQuick Voyager).
.ADT  AdTech fax file (AdTech Fax).
.ADT  Auction Designer Template file (Auction Designer 3).
.ADT  Check drawing integrity Diagnostic Tool report file = ASCII text (CorelCAD).
.ADT  Database file (Advantage Data Server).
.ADT  Dictionary file (Lingo).
.ADT  HP NewWave Card Application Data file.
.ADTS ADTS audio file (QuickTime Player 7.7.2).
.ADV  Adventure data file.
.ADV  Audio Driver file for sound cards (DOS/MS-DOS games).
.ADV  GUS virtual device Driver file.
.ADX  Archetype Designer document file (Archetype Designer).
.ADX  Dynazip Active Delivery script file.
.ADX  Index file (Lotus' Approach).
.ADZ  GZ compressed Amiga Disk file (Amiga Forever and other Amiga operating system emulators).
.AE   Author/Editor file (SoftQuad's HoT MeTaL Pro).
.AEDLAYOUT Auto-Run Editor Layout file (Ashampoo Burning Studio 11).
.AEDTHEME Auto-Run Editor Theme file (Ashampoo Burning Studio 11).
.AEP  After Effects Project file (Adobe After Effects).
.AEP  ArcExplorer Project file (ArcExplorer).
.AEPX After Effects Project XML file (Adobe After Effects).
.AES  Advanced Encryption Standard encrypted file (AES Crypt and any encryption/decryption applications supporting the Advanced Encryption Standard).
.AES  After Effects Stabilizer settings file (Adobe After Effects).
.AET  After Effects Transfer settings file (Adobe After Effects).
.AEU  Europe Route file (Microsoft's AutoRoute Express).
.AEX  Adobe Extra transfer modes plug-in file (Adobe Systems' After Effects).
.AEX  Armored Extracted Public Encryption Key file (Pretty Good Privacy).
.AF2  ABC Flowchart v2 file (ABC FlowChart).
.AF3  ABC Flowchart v3 file (ABC FlowChart).
.AFC  Apple Format Compressed audio file (Audio applications).
.AFC  ArisFlow Commander file (ArisFlow).
.AFD  ActiveFile Data file (Prismo Graphics ActiveFile).
.AFD  After Dark file (After Dark screensaver application).
.AFD  ArisFlow Diagram file (ArisFlow).
.AFF  Affixes, prefixes, suffixes file (many applications).
.AFF  AnyForm Form file (AnyForm).
.AFFIX Affixes file (AbiSource's AbiWord).
.AFI  Truevision bitmap graphic image file (Image editors).
.AFL  Lotus Font file (Lotus 1-2-3).
.AFM  Adobe Font Metrics file for Adobe type font files (many applications).
.AFM  Cardfile Application file (HP NewWave).
.AFP  ActiveFile Proxy file (Prismo Graphics ActiveFile).
.AFP  Ameol File transfer Protocol application (CIX's Ameol2).
.AFP  Flowchart symbol Palette file.
.AFS  Audio File (Sega systems).
.AFT  ABC Flowchart Template file (ABC Flowchart).
.AFT  AnyForm Template file (AnyForm).
.AFT  Audio Filter plug-in library file (Ulead Systems MediaStudio 5).
.AFW  ABC Flowchart Work Area file (ABC Flowchart).
.AG   Applix Graphic image file.
.AG   Argus spreadsheet file.
.AG4  Access G4 file.
.AGF  Atlas GeoFile format file.
.AGP  Video driver documentation for AGP video card.
.AHF  ASP document Header File.
.AHK  Auto Hotkey hotstrings file (Bartels Media PhraseExpress).
.AHN  Ahnenblatt database file (Ahnenblatt geneaology program).
.AHN  Ahnenblatt family tree file (Ahnenblatt geneaology program).
.AHQ  AudioHQ plug-in file (Creative soundcard EAX effects control).
.AHS  Adobe Photoshop Half-tone Screens file (Adobe Photoshop).
.AHU  Adobe Photoshop Hue and Saturation adjustment/settings file (Adobe Systems Photoshop).
.AHY  AutoHotKey file.
.AI   Adobe Illustrator vector drawing file. A number of different variants all native to that program. Some third party graphics applications support it (Adobe Illustrator).
.AI   After Image file (Progress Database).
.AI   Corel Trace drawing file = Adobe Illustrator format (Corel's CorelDRAW).
.AIF  Application Information File (Symbian operating systems).
.AIF  Audio Interchange File Format/AIFF uncompressed audio file (Apple QuickTime).
.AIFC Audio Interchange File Format Compressed audio file (QuickTime 7.7.2).
.AIFF Audio Interchange File Format uncompressed audio file (Apple QuickTime).
.AIFF Macintosh AIFF uncompressed audio file (Many applications).
.AIJ  After-Image Journal file.
.AIM  AOL Instant Messenger shortcut file (America OnLine/AOL Instant Messenger).
.AIML Artificial Intelligence Markup Language file (Plaintext markup).
.AIMPPL AIMP3 Playlist file (AIMP Player 3).
.AIN  AIN compressed archive file.
.AIO  APL Input/Output format file.
.AIR  Air installer package file (Application distributions installed with Adobe Air).
.AIS  Album/Image Sequence file (ACD Systems' ACDSee).
.AIS  Array of Intensity Samples format image file (Image editor/viewer applications).
.AIX  AIX Unix documentation file for applications designed for multiple operating systems.
.AIX  Cardfile Application data file (HP NewWave).
.AKB  Assistum Knowledge Base file (Assistum).
.AKF  Acrobat Key File (Adobe Acrobat).
.AKS  ArtWeaver Keyboard Shortcuts file (Boris Eyrich Software Artweaver).
.ALB  Album file (Jasc Media Center Plus).
.ALB  Album/playlist file (Carlanthano Player = Radiate-infested adware).
.ALB  Backup file (Steinberg Cubase).
.ALB  JASC Image Commander Album (JASC Image Commander).
.ALB  Photo album/thumbnail set file.
.ALB  Web project Album file (ixla Web Easy).
.ALBM Photo Album file (webAlbum).
.ALBM Photo printing Album file (HP Photosmart).
.ALD  DVD Album project file (Anix' DVD Album).
.ALE  Advanced Landscape Editor project file (Dyvision Works' Advanced Landscape Editor).
.ALE  Avid Log Exchange file.
.ALF  ACT! file.
.ALIAS Alias Image (many image applications).
.ALL  Documentation/text file = For all users/operating systems.
.ALN  Align project file (Visual Computing Lab - ISTI - CNR's MeshLab).
.ALS  Alias image file (many image applications).
.ALT  ALT file (WordPerfect Corporation WordPerfect).
.ALV  Adobe Photoshop Levels file (Adobe Photoshop).
.ALV  Vbox Available Languages file (Aladdin Knowledge Systems software distribution).
.AM   Amplitude Modulation monophonic audio file.
.AM   Applix Macro file (Applix Shelf).
.AM2  AutoPlay Menu Studio 2 file (Indigo Rose's AutoPlay Menu Studio).
.AM3  AutoPlay Menu Studio 3 file (Indigo Rose's AutoPlay Menu Studio).
.AM4  AutoPlay Media Studio 4 file (Indigo Rose's AutoPlay Media Studio).
.AMB  Radiance Ambient format file.
.AMC  AMC movie file (QuickTime 7.7.2).
.AMC  Ant Movie Catalog file (Ant Movie Catalog).
.AMF  Additive Manufacturing File Format file = XML-based.
.AMF  Advanced Module Format audio file.
.AMH  AudioMulch document file (Ross Bencina's AudioMulch).
.AMI  AmiDiag file.
.AMI  Amiga Paint image file (many image applications).
.AMIO Amio Plug-in file (Adobe Systems' Audition).
.AML  AutoMage file.
.AML  Automate Markup Language file.
.AMP  Adobe Photoshop Arbitrary Map settings file (Adobe Photoshop).
.AMR  Adaptive Multi-Rate audio file (QuickTime 7.7.2).
.AMS  Adobe Photoshop Monitor Setup file (Adobe Photoshop).
.AMS  AudioMulch Set file (Ross Bencina's AudioMulch).
.AMS  Extreme's Tracker Module file.
.AMSF Auto-Run Maker Saved Files file (Abhishek's Auto-Run Maker).
.AMZ  Game save file (The Amazon Trail).
.AN8  Anim8or 3D animation file (Anim8or).
.ANI  Animated cursor file (Microsoft Windows, Impact's Microangelo and other image applications).
.ANIMATION Animation project file (Insane Tools' 3D Flash Animator 3).
.ANL  Analysis file (Project Analyzer).
.ANM  Animation image file (DeluxePaint Animator).
.ANM  Jamagic animation file (Clickteam Jamagic).
.ANN  Annotation file (Windows operating system Help system/HELP.EXE).
.ANO  Annotation file.
.ANS  ANSI image file.
.ANT  SimAnt game save file (Maxis/Imagineer's SimAnt).
.ANV  AirNav file (many image applications).
.AOB  DVD audio file (MPEG-2 program streams with additional info).
.AOF  Acorn Object Format file.
.AOI  Art Of Illusions file (Peter Eastman's Art Of Illusions).
.AOM  After Effects Output settings file (Adobe After Effects).
.AOS  Add-on/plug-in file.
.AP   Application file.
.AP   Application information file (driver installers - SiS, Cmedia, etc).
.AP   WHAP archive file (Amiga operating system and emulators).
.APA  AlfaPad file (AlfaAlfa Software AlfaPad).
.APA  Applet file (ArcPad).
.APC  Assistum Project Case scenario file (Assistum).
.APD  Aml Pages Document file (Mazov Gosha's Aml Pages notes manager).
.APE  Monkey Audio APE lossless audio format file (Many applications).
.APF  Acrobat Profile file (Adobe Acrobat).
.APF  Animator Project File (SanoLogic gr44 Animator).
.APF  Profile file (ArcPad).
.APF  Project File (Homesite).
.API  Adobe Photoshop Printing Inks color configuration file (Adobe Photoshop).
.API  Aml Pages Import file (Mazov Gosha's Aml Pages notes manager).
.API  Application Plug-In file (KetilO's FbEdit FreeBASIC Editor).
.API  Application Program Interface/driver file (many applications).
.APIN APIN plug-in file (Adobe InDesign).
.APJ  ARM Project file (ARM Project Manager).
.APK  Ad Packed file = packed graphic image (UltraPlayer).
.APK  Archive. PK=PK ZIP. The extension is used in cellphones and other usually portable devices.
.APL  ACDSee32 Plug-in file (ACD Systems' ACDSee v3.1).
.APL  Adobe Photoshop Plug-in file (Adobe Photoshop and many other image editors).
.APL  APL workspace file.
.APL  APlus Encrypted folder file (A+ Folder Locker).
.APL  ArcPad Layer file (ArcPad).
.APL  Plug-in file (AceHTML).
.APM  ArcPad file (ArcPad).
.APO  Apollo script file.
.APP  Application file (Clarion).
.APP  Application file (Many operating systems, programs, and many variants).
.APP  Application object file (Ashton Tate dBASE).
.APP  ArcPad Project file (ArcPad).
.APPCACHE Appcache manifest file.
.APPLICATION Application deployment manifest file (Microsoft Windows).
.APPREF-MS Application deployment reference file (Microsoft Windows).
.APR  Approach data file (Lotus Approach 97).
.APS  Assistum Project Space file (Assistum).
.APS  Microsoft Visual C++ file.
.APS  Symbology file (ArcPad).
.APT  Approach Data View file (Lotus Approach 97).
.APT  Alphacam Punch Tool/APT file (IGESToolbox).
.APTHME Aml Pages Theme file (Mazov Gosha's Aml Pages notes manager).
.APX  Ability Photopaint image file (Ability Photopaint).
.APX  Appexpert file (Borland Appexpert).
.APX  Approach file (Lotus Approach 97).
.APX  ArcPad XML file (ArcPad).
.AR   Archive/Archive distribution file (Many games and applications, many variants).
.ARA  ATI Radeon driver file (ATI video cards).
.ARC  ARC format archive container file (Many OSs and variants).
.ARC  Archimedes drawing file = XML markup (Tarantulus' Archimedes the Open CAD).
.ARCHIMEDES Snapshot file (Speccy).
.ARG  ArrangeNote file (KYamamoto's ArrangeNote).
.ARJ  ARJ format archive container file (Many archiving applications).
.ARK  ARK format archive container file.
.ARN  Astronomical Research Network file (many image applications).
.ARN  Autoruns saved registry scan results file (SysInternals' Autoruns).
.ARPX8 Arp-X8 MIDI arpeggiator file.
.ARQ  Archive file.
.ARR  Arrangement file (Audio applications).
.ARS  After Effects Render Settings file (Adobe After Effects).
.ART  America Online ART file (Many image editors and viewers).
.ART  Another Ray Tracer format image file (Many image editors and viewers).
.ART  Art Director image file (Art Director).
.ART  Artisan file.
.ART  Canon Crayola Art file.
.ART  Clip Art file (many image applications).
.ART  Drawing file (Xara Studio).
.ART  PFS: Art Publisher file (many image applications).
.ARV  Arsiv file.
.ARV  AutoRoute User Information file.
.ARW  Sony DSLR RAW format image file (Many variants).
.ARW  Sony RAW format image file (Sony cameras, many image applications, many variants).
.AS   Action Script file (Macromedia/Adobe Flash development and web developer applications).
.AS   Apple Single format archive container file (Smith Micro's Stuffit and other archive applications).
.AS   Applix Spreadsheet file.
.AS4  AS/400 client access file.
.ASA  Active Server document file (August Wind's ASP Express).
.ASC  3D Studio ASCII format file (Draw3D).
.ASC  ActionScript source code file (Text highlighting text editors and web developer applications).
.ASC  ASCII text file (Many applications).
.ASC  Assembler Source Code file.
.ASD  Advanced Streaming Format Description file = Accompanies Microsoft ASF video/audio files or directs applications to Microsoft ASF content (Many applications).
.ASD  ASF Descriptor file (Microsoft Windows Media Encoder).
.ASD  Astound Presentation file.
.ASD  Auto-Saved Document file (Microsoft Word).
.ASD  Screen Driver file.
.ASDB Archive System Database file = Media catalog (Sayyid Mohammad Saleh Samimi's Archive System 1.9).
.ASES Audition Session Plug-in file (Adobe Systems' Audition).
.ASF  Active Streaming Format file (A proprietary Microsoft streaming media container format).
.ASF  Lotus Screen Font file.
.ASF  Statgraphics data file.
.ASH  ArtWeaver custom Shape file (Boris Eyrich's ArtWeaver).
.ASH  ArtWeaver Shape file (Boris Eyrich Software Artweaver).
.ASH  Assembler Header file (TASM assembler).
.ASHDISC AShampoo Disc image file (Power Software's Free Any Burn).
.ASHLANG Ashampoo Language localization file (Ashampoo's Burning Studio).
.ASI  Assembler Includes file (Borland Assembler).
.ASK  askSam database file.
.ASM  Assembly language source code file (Virtually all systems/OSs and their assembly/disassembly applications that have assembly programming facilities use this extension).
.ASM  Generic Assembler source code file (Digia Qt Creator).
.ASMX ASP.NET Webservices source file.
.ASN  Assistum Scenario file (Assistum).
.ASO  Assembler Object file.
.ASP  Active Server Page/Document file (Servers, browsers, web developer environments).
.ASP  Adobe Photoshop color Separation setup file (Adobe Photoshop).
.ASP  ASPECT program file (Procomm Plus).
.ASPX ASP.NET source file.
.ASR  Microsoft Automap route file.
.ASRC ARM microprocessor Assembly Source code file.
.ASS  Advanced Substation Alpha format sub-titles file (Aegisub).
.ASS  Assembly language source code file (Many applications).
.AST  Adobe Photoshop color Separation Table file (Adobe Photoshop).
.AST  Assistant file (Claris Works' Assistant).
.AST  Assistant file (Corel Office X6 PerfectExpert Assistant).
.AST  Astound! media file (Astound!).
.ASV  Adobe Photoshop Selective color adjustments file (Adobe Photoshop).
.ASV  Auto-Saved document/project file (QuarkXPress).
.ASV  Auto-Saved file (DataCAD).
.ASX  Advanced Streaming Redirector file = Microsoft's playlist format for MediaPlayer. Unfortunately, some applications use this extension to store video and/or audio, so manual content determination is often required.
.ASX  Cheyenne Backup script file.
.AT2  Auto Template file (Aldus Persuation 2).
.ATF  Adobe Photoshop Transfer Functions file (Adobe Photoshop).
.ATK  Andrew Toolkit bitmap image file (Andrew Toolkit).
.ATM  Adobe Type Manager database file (Adobe Systems' Type Manager).
.ATN  Actions file (Adobe graphics/image applications).
.ATP  Accel spreadsheet/worksheet Template file (SSuite Office Accel).
.ATR  Material library file (Lightscape).
.ATT  AT&T Group 4 bitmap format image file = the standard fax image format (Many fax devices/applications and image applications).
.ATU  aTunes playlist file (aTunes Team aTunes).
.AU   Linear or µ-law/Mu-Law compressed audio file (QuickTime and many other audio applications).
.AU3  AutoIt version 3 script (Image and Text editors).
.AUCTIONFERRETSEARCH AuctionFerret saved Search file (AuctionFerret).
.AUD  Audio file (many applications).
.AUP  Audacity native Project file (Audacity Team's Audacity).
.AUR  Aura project file (Hervé Adam's Aura).
.AUT  Authentication/verification file (Many applications).
.AUT  Auto-Illustrator file.
.AUT  AutoIt script file (AutoIt).
.AUTHEDTHEME Authoring Editor Theme file (Ashampoo Burning Studio 11).
.AUX  Auxilliary dictionary file (ChiWriter).
.AVA  Adobe Photoshop Variations file (Adobe Photoshop).
.AVA  Avagio file.
.AVASTCONFIG Avast configuration file (Avast Virus).
.AVASTLIC Avast License file (Avast Virus).
.AVASTSOUNDS Avast! Sound package file (Avast! Antivirus).
.AVASTTHEME Theme file (Avast Virus).
.AVB  Character file (Microsoft Chat).
.AVC  Kaspersky Antivirus Toolkit file.
.AVD  Avery Data file (Avery Label Pro).
.AVE  Avenue file (ActiveState's Komodo Edit).
.AVI  Microsoft Audio Video Interleave file (QuickTime 7.7.2 and many other video applications).
.AVL  AV List slideshow file (AV List).
.AVP  Avid Project file.
.AVPRESET Audio/Video project configuration file (Dominique Levray's ffDiaporama).
.AVR  AV Research audio file (Audio applications).
.AVS  Advanced Visualization Studio plug-in file (Nullsoft WinAmp).
.AVS  Animation project file.
.AVS  Avisynth File (scripting language and filters for non-linear video editing).
.AVS  Stardent AVS X Image file (image applications).
.AVSI AviSynth file.
.AW   AdvanceWrite Text file (HP AdvanceWrite).
.AW   Answer Wizard file = a file supporting the Answer Wizard help querying system found in Microsoft applications (Microsoft Windows, Microsoft Office and other Microsoft application suites).
.AW   Applix Words document file (Applix Words).
.AWB  Ad-Aware Backup file (LavaSoft AdAware).
.AWC  Another World Creator file (Juan Ignacio Odriozola's Another World Creator).
.AWD  ArtWeaver Document file (Boris Eyrich Software Artweaver).
.AWD  Award BIOS logo file.
.AWD  Fax file (Microsoft Fax).
.AWE  ArtWeaver Events file (Boris Eyrich Software Artweaver).
.AWK  AWK programming language script/program file (Unix/Linux' AWK utility and AWK utilities in other operating systems).
.AWL  AudioWriter Layout file (R.M. de Boer Software's AudioWriter).
.AWM  AnimationWorks Movie file.
.AWR  Ad-Aware file (LavaSoft Ad-Aware).
.AWT  AbiWord document Template file (AbiSource AbiWord).
.AWTEAM ArtWeaver Team file (Boris Eyrich Software Artweaver).
.AX   DirectX/DirectShow filter file (Microsoft Windows operating system).
.AXE  Autoroute Export file (Microsoft Autoroute).
.AXP  CDBurnerXP file (Canneverbe CDBurnerXP 4).
.AXT  Adobe Photoshop color replacement file (Adobe Photoshop).
.AY   AY soundchip file (Game/OS emulators).
.AZ   WinDVD file.
.AZZ  AZZ AvCardfile Personal Information Manager file.
.AZZ  Compressed AZZ cardfile (Antanas Zdramys' azzCardfile 4).
.AZZX Uncompressed AZZ cardfile (Antanas Zdramys' azzCardfile 4).

 Updated 11/24/2013