This chart is a list of the most commonly found extensions, what type of file they are and what program if any they are associated with.
.$$$ Temporary file
.$$A OS/2 program file
.$$F OS/2 database file
.$$S OS/2 spreadsheet file
. OS/2 planner file
.$DB DBASE IV temporary file
.$ED Microsoft C temporary editor file.
.$VM Microsoft Windows temporary file for virtual managers.
._DD Norton disk doctor recovery file.
._DM Nuts n Bolts disk minder recovery file.
.--- File used to backup sys, ini, dat, and other important files from Windows 3.1 and above.
.075 Ventura Publisher 75x75 dpi screen characters
.085 Ventura Publisher 85x85 dpi screen characters
.091 Ventura Publisher 91x91 dpi screen characters
.096 Ventura Publisher 96x96 dpi screen characters
.0B Pagemaker printer font LineDraw enhanced characters.
.1ST File used by some software manufacturers to represent a file that should be read first before starting the program.
.2GR File used in Windows 3.x to display the graphics on older 286 and 386 computers.
.386 Virtual machine support files for the 386 enhanced mode.
.3GR File used in Windows 3.x to display the graphics on later 386, 486 and Pentium computers.
.4SW 4DOS Swap file
A
A ADA program file or UNIX library
.A3W MacroMedia Authorware 3.5 file
.ABK Autobackup file used with Corel Draw 6 and above.
.ABR Brush file for Adobe Photoshop
.ACT Adobe Photoshop Color table file.
.AD After Dark file.
.ADF Adapter description files.
.ADM After Dark screen saver module.
.ADR After Dark randomizer
.AI Adobe Illustrator file.
.AIF Auto Interchange File Format (AIFF) Audio file.
.ANI Windows 95 / Windows 98 / Windows NT animated mouse cursor file.
.ANS ANSI text file.
.ARJ Compressed file can be used with Winzip / Pkzip.
.ASC ASCII Text file
.ASF Sort for Advanced Streaming Format, file developed by Microsoft. The .ASF file is generally a movie player and can be open with software such as Windows Media Player.
.ASP Microsoft FrontPage Active Server Pages. To open these files use your internet browser.
.AVI Windows Movie file.
B
.BAK Backup file used for important windows files usually used with the System.ini and the Win.ini.
.BAS QBasic program and or Visual Basic Module.
.BAT Batch file that can perform tasks for you in dos, like a macro.
.BFC Microsoft Windows 95 / Windows 98 Briefcase file.
.BG Backgammon game file.
.BIN Translation tables for code pages other than the standard 437.
.BK2 Word Perfect for Windows Backup file
.BK3 Word Perfect for Windows Backup file
.BK4 Word Perfect for Windows Backup file
.BK5 Word Perfect for Windows Backup file
.BK6 Word Perfect for Windows Backup file
.BK7 Word Perfect for Windows Backup file
.BK8 Word Perfect for Windows Backup file
.BK9 Word Perfect for Windows Backup file
.BMP Graphical Bit Mapped File used in Windows Paintbrush.
.BNK Sim City Backup
.BPS Microsoft Works Word Processor File.
.BPT Corel Draw Bitmap master file
.BV1 Word Perfect for Windows Backup file
.BV2 Word Perfect for Windows Backup file
.BV3 Word Perfect for Windows Backup file
.BV4 Word Perfect for Windows Backup file
.BV5 Word Perfect for Windows Backup file
.BV6 Word Perfect for Windows Backup file
.BV7 Word Perfect for Windows Backup file
.BV8 Word Perfect for Windows Backup file
.BV9 Word Perfect for Windows Backup file
.BWP BatteryWatch pro file.
C
.C C file used with the C programming language.
.CAB Cabinet file used in Windows 95 and Windows 98 that contains all the windows files and drivers. Information about how to extract a .CAB file can be found on document CH000363.
.CAL Windows Calendar, Supercalculator4 file or Supercal spreadsheet.
.CBL COBOL Program File
.CBT Computer Based Training files.
.CDA CD Audio Player Track.
.CDR Corel Draw Vector file.
.CFB Comptons Multimedia file
.CFG Configuration file
.CFL Corel flowchart file
.CFM Corel FontMaster file / Cold Fusion Template file / Visual dBASE windows customer form
.CHK Scandisk file which is used to back up information that scandisk has found to be bad, found in C root. Because the information within these files are corrupted or reported as bad by Scandisk it is perfectly fine to delete these files, providing you are currently not missing any information. Additional information about scandisk can be found on our scandisk page.
.CL Generic LISP source code.
.CL3 Easy CD Creator layout file.
.CL4 Easy CD Creator layout file.
.CLA Java Class file.
.CLG Disk catalog database
.CLK Corel R.A.V.E. animation file.
.CLL Crick software clicker file
.CLO Cloe image
.CLP Windows Clipboard / Quattro Pro clip art / Clipper 5 compiler script
.CLR WinEdit Colorization word list / 1st reader binary color screen image / PhotStyler color definition
.CLS Visual Basic Class module / C++ Class definition
.CMD Windows Script File also OS/2 command file.
.CMV Corel Movie file.
.CNT Help file (.hlp) Contents (and other file contents)
.CPL Windows 95 / Windows 98 / Windows NT control panel icons.
.CNE Configuration file that builds .COM files.
.CNF Configuration file.
.COB COBOL source code file.
.COD FORTRAN Compiler program code
.COM File that can be executed.
.CPE Fax cover page file
.CPI Code Page Information or Microsoft Windows applet control panel file
.CPP C++ source code file.
.CRD Windows Card file.
.CSV Comma-Separated Variable file. Used primary with databases and spreadsheets / Image file used with CopuShow
.CUR Windows Mouse Cursor.
.CVS Canvas drawing file
.CXX C++ program file or Zortech C++ file
D
.DAT Data file, generally associated or extra data for a program to use.
.DB Paradox database file / Progress database file
.DB2 dBase II file
.DBC Microsoft Visiual Foxpro database container
.DBF dBase II,III,III+,IV / LotusWorks database.
.DBK dBase databse backup / Orcad schematic capture backup file
.DBM Cold Fusion template
.DBO dBase IV compiled program file
.DBQ Paradox memo
.DBT dBase database text file
.DBV Flexfile memo field file
.DBW DataBoss database file
.DBX Database file / DataBeam Image / MS Visual Foxpro Table
.DEV Device Driver
.DIF Document Interchange Format; VisiCalc
.DLL Dynamic Link Library; Allow executable code modules to be loaded on demand, linked at run time, and unloaded when not needed. Windows uses these files to support foreign languages and international/nonstandard keyboards.
.DMO Demo file
.DMP Dump file
.DMD Visual dBASE data module
.DMF Delusion/XTracker Digital Music File
.DMO Demo file
.DMP Dump file
.DMS Compressed archive file
.DOC Microsoft Word Windows/DOS / LotusWorks word processor Windows/DOS /PF S:First Choice Windows/DOS DOT MS Word Windows/DOS.
.DOS Text file and DOS Specification Info
.DOT Microsoft Word Template (Macro).
.DRV Device driver files that attach the hardware to Windows. The different drivers are system, keyboard, pointing devices, sound, printer/ plotter, network, communications adapter.
.DRW Micrografx draw/graph files.
.DT_ Macintosh Data File Fork
.DTA Data file
.DTD SGML Document definition file
.DTF Q&A database
.DTM DigiRekker module
.DTP SecurDesk! Desktop / Timeworks Publisher Text Document / Pressworks Template file
.DUN Dialup Networking exported file.
.DX Document Imaging file / Digital data exchange file
.DXB Drawing interchange binary file
.DXF Autocad drawing interchange format file
.DXN Fujitsu dexNet fax document
.DXR Macromedia director projected movie file
.DYN Lotus 1-2-3 file
.DWG AutoCad Drawing Database
E
.EEB Button bar for Equation Editor in Word Perfect for Windows
.EFT CHIWRITER high resolution screen characters
.EGA EGA screen characters for Ventura Publisher
.ELG Event List text file used with Prosa
.EMS Enhanced Menu System configuration file for PC Tools
.EMU IRMA Workstation for Windows emulation
.ENC ADW Knowledge Ware Encyclopedia
.END Corel Draw Arrow Definition file
.ENG Sprint dictionary file engine
.ENV Word Perfect for Windows environment file.
.EPG Exported PaGe file used with DynaVox
.EPS Encapsulated Postscript, with embedded TIFF preview images.
.EQN Word Perfect for Windows Equation file
.ERD Entity Relation Diagram graphic file
.ERM Entity Relation Diagram model file
.ERR Error log file
.ESH Extended Shell Batch file
.EVT Event file scheduler file for PC Tools
.EX3 Device driver for Harvard graphics 3.0
.EXC QEMM exclude file from optimization file or Rexx program file
.EXE Executable file.
.EXT Extension file for Norton Commander
F
.FDF Adobe Acrobat Forms Document.
.FF AGFA CompuGraphics outline font description.
.FFA Microsoft Fast Find file.
.FFF GUS PnP bank / defFax fax document
.FFL Microsoft Fast Find file / PrintMaster Gold form file
.FFO Microsoft Fast Find file
.FFT DCA/FFT final form text
.FFX Microsoft Fast Find file
.FON Font files to support display and output devices.
.FR3 dBase IV renamed dBase III+ form
.FRF FontMonger Font
.FRG dBase IV uncompiled report
.FRK Compressed zip file used with Apple Macinotsh computers.
.FRM Form file used with various programs / Microsoft Visual Basic Form / FrameMaker document / FrameBuilder file / Oracle executable form / Word Perfect Merge form / DataCAD symbol report file
.FRO dBase IV compiled report / FormFlow file
.FRP PerForm Pro Plus Form
.FRS WordPerfect graphics driver
.FRT FoxPro report file
.FRX Microsoft Visual basic binary form file / FoxPro report file
.FRZ FormFlow file
G
.GIF CompuServe Graphics Interchange Format.
.GR2 286 grabbers that specify which font to use with DOS and Windows.
.GR3 386 grabbers that specify which font to use with DOS and Windows.
.GRA Microsoft Flight simulator graphics file
.GRB Microsoft MS-DOS shell monitor
.GRF Micrografx draw/graph files.
.GRP Microsoft Program Group.
.GZ Compressed Archive file for GZip
H
.HBK Mathcad handbook file
.HDL Procomm Plus alternate download file listing
.HDR Procomm Plus message header
.HDX Help index
.HEX Hex dump
.HFI GEM HP font info
.HGL HP graphics language graphic
.HH C++ Header
.HHH Precompiled Header for Power C
.HHP Help data for Procomm Plus
.HLP Files that contain the Help feature used in windows, cannot be read from DOS.
.HQX Apple Macintosh Binhex text conversion file.
.HSQ Data files associated with the Qaz Trojan.
.HSS Photoshop Hue/Saturation information.
.HST History file / Procomm Plus History File / Host file.
.HTA Hypertext Application (run applications from HTML document).
.HTM Web page files containing HTML or other information found on the Internet.
I
.ICA Citrix file / IOCA graphics file
.ICB Targa Bitmap
.ICC Kodak printer image
.ICE Archive file
.ICL Icon library file
.ICM Image Color Matching profile file
.ICN Microsoft Windows Icon Manager.
.ICO Microsoft Windows Icondraw / Icon.
.ID Disk identification file.
.IDB Microsoft developer intermediate file, used with Microsoft Visual Studio
.IDD MIDI instruments definition
.IDE Integrated Development Environment configuration file
.IDF MIDI instruments drivers file
.IDQ Internet data query file
.IDX Index file
.IFF IFF/LBM (Amiga) used by Computer Eyes frame grabber.
.IMG GEM/IMG (Digital Research) or Ventura Publisher bitmap graphic
.INF Information file that contains customization options.
.INI Files that initialize Windows and Windows apps.
.IPF Installer Script File / OS/2 online documentation for Microsoft source files.
.ISO Compressed file used for an exact duplicate of a CD. .ISO files can be extracted or opened such programs as Win Image that can be found on our shareware download section.
.IWA IBM Writing Assistant Text file.
J
.JAS Graphic
.JPG Graphic commonly used on the Internet and capable of being opened by most modern image editors.
.JS JavaScript file.
.JSB Henter-Joyce Jaws script binary file
.JSD eFAX jet suite document
.JSE JScript encoded script file
.JSH Henter-Joyce Jaws script header file
.JSL PaintShop pro file
.JSM Henter-Joyce Jaws script message file
.JSP Java server page
.JSS Henter-Joyce Jaws script source file
.JT JT fax file
.JTF JPEG tagged Interchange format file
.JTK Sun Java toolkit file
.JTP JetForm file
.JW Justwrite text file
.JWL Justwrite text file library
.JZZ Jazz spreadsheet
K
.KAR Karaoke File used with some audio players.
L
.LGC Program Use Log File (for Windows Program Use Optimization).
.LGO Contains the code for displaying the screen logo.
.LOG Contains the process of certain steps, such as when running scandisk it will usually keep a scandisk.log of what occurred.
.LNK HTML link file used with Microsoft Internet Explorer.
.LWP Lotus Wordpro 96/97 file.
M
.MAC Macintosh macpaint files.
.MBX Microsoft Outlook Express mailbox file.
.MD Compressed Archive file
.MDA Microsoft Access Add-in / Microsoft Access 2 Workgroup.
.MDB Microsoft Access Database / Microsoft Access Application.
.MDE Microsoft Access Database File
.MDF Menu definition file
.MDL Digitrakker Music Module / Rational Rose / Quake model file
.MDM Telix Modem Definition
.MDN Microsoft Access Blank Database Template
.MDP Microsoft Developer Studio Project
.MDT Microsoft Access Add-in Data
.MDW Microsoft Access Workgroup Information
.MDX dBase IV Multiple Index
.MDZ Microsoft Access Wizard Template
.MEB WordPerfect Macro Editor bottom overflow file
.MED WordPerfect Macro Editor delete save / OctaMed tracker module
.MEM WordPerfect Macro Editor macro / Memory File of variables
.MID Midi orchestra files that are used to play with midi sounds built within the sound card.
.MIX Power C object file / Multiplayer Picture file (Microsoft Photodraw 2000 & Microsoft Picture It!) / Command & Conquer Movie/Sound file
.MOD Winoldap files that support (with grabbers) data exchange between DOS apps and Windows apps.
.MOV File used with Quick Time to display a move.
.MP1 MPEG audio stream, layer I
.MP2 MPEG audio stream, layer II
.MP3 MPEG audio stream, layer III; High compressed audio files generally used to record audio tracks and store them in a decent sized file available for playback. See our MP3 page for additional information.
.MPG MPEG movie file.
.MSN Microsoft Network document / Decent mission file
.MTF Windows metafile.
.MTH Derive Math file
.MTM Sound file / MultiTracker music module
.MTV Picture file
.MTW Minitab data file
.MU Quattro menu
.MUL Ultima Online game
.MUP Music publisher file
.MUS Audio file
.MVB Database file / Microsoft multimedia viewer file
.MVE Interplay video file
.MVF Movie stop frame file
.MWP Lotus Wordpro 97 smartmaster file
.MXD ArcInfo map file
.MXT Microsoft C Datafile
.MYD Make your point presentation file.
