How many times you have confronted a situation where you receive (through E-Mail) or you just find a file with an "extension" that you don't recognize ?

This is a small recompilation of the most common file extentions on your Computer.

I hope it enlightens you and I wish you a pleasant learning experience !

*.acl   Access-Code-Library for Windows
*.acm   Advanced Color-Driver-Modul
*.aif   Internet Audio File
*.ani   Animated cursor
*.arc   Compressed Data in LHARC-Format
*.asc   PRO-CD Search Criteria-Initializing
*.asp   ASP Shareware Text (Active Server Page)
*.au    Audio-Basic-File
*.avi   Windows animated Video-File
*.b~k   Copy of a BackUp Copy
*.bak   Copy of a *.bat file
*.bas   Symbol List Initializing; BASIC-Sourcecode
*.bat   Batchdata to execute a program
*.bfc   Win 95 Briefcase Data
*.bin   Zipping Program (Compress) Data
*.bmp   Windows-/OS2-Bitmap Grafic (Background picture, etc.)
*.btx   BTX-Decoder-File
*.cab   Cabinet of DOS-Modules
*.cag   Corel Art Gallery
*.cal   Calender Data (Microsoft)
*.cb    Program specific BackUp copie
*.cch   COREL Chart Data
*.cda   CD-Audio-Track
*.cdr   COREL Draw Picture
*.cdt   COREL Symbol Infokey Modul
*.cfg   Configuration Data
*.cim   BackUp Copy for WinCIM
*.cla   Hot Java Browser classification for Netscape
*.cmp   GIF Construction Backup Graphics File
*.cmv   COREL Move Datei
*.cmx   COREL Presentation
*.cnt   Calender-Save element
*.cnv   Word Converter-Modul
*.com   Executes a Program Group
*.cor   BackUp Copy for COREL
*.cp$   Error Code Dos Calls (Telephone)
*.cpi   DOS-Font-Registry
*.cpl   Codepage Listing for System's saved options
*.cpt   COREL Photo-Paint Image
*.crd   Card Data (Microsoft)
*.csv   Excel Script-Format Data
*.cur   Mouse Icon
*.cvp   Delrina Winfax 3.0 Cover page data
*.dat   Data-File (D-Info etc. etc.)
*.db    Database general
*.dba  Paradox-Tabel
*.dbf   Databank in dBase-Format
*.dic   User diccionary
*.dif    Excel Datatransfer File
*.dl     Old Library-File from Win 3.1
*.dll    Actual Library-Files
*.doc  MS Word Document
*.dos  Windows 95 DOS-Systemdata
*.dot   MS Word Document Model
*.drv   Driver
*.ds4   Micrografx Designer 4.0 File
*.dsg   COREL Query File

*.eng   History of Revision in English
*.eps   Micrografx Graphic Engine for conversion
*.equ   Word Equipped Simbol Coverter
*.ex_    Not Unzipped Data (Programm)
*.exe   Programm

*.flc   Videosecuence in FLIC-Format
*.fli    Videosequence in special FLIC-Format
*.flt    Grafic Runtime-Modul
*.fmt  Formated Print Datai for MS Schedule+
*.fnd  Saved search in Explorer (Win95)
*.fnt   DOS-System-Terminal-Fonts
*.fog  Fontographer Font-Data
*.fot   normal Fonts
*.frm  OLE-Automations-Modul
*.fxd   Fax-Data(Winfax 3.0)
*.fxr   Fax-Receive Data (Winfax 3.0)
*.fxs   Fax-Send Data  (Winfax 3.0)
*.ger   History of Revision in German
*.gif     Graphic Image Format C 89a (Picture-Data)
*.gra   Graph 5 - Init Data
*.grp   Programgroup for Windows
 *.hlp    Help data from a Program
*.hot    Internet-Browser Hotlists
*.hpp   Homepages (m. Homepage Wizzard erstellt)
*.hpw  Homepage Wizard Data
*.hst    Netscape Host-File
*.ht      Hyperterminal-System data
*.htm / *.html   HTML -Internet Data

*.icc    Intelligent Color Charting (Printer)
*.icm   Intelligent Color Matching Library
*.ico    Icon-Data
*.id      Identification Data on installation Diskette
*.idf     Midi-Instrument Identification
*.in_    Not unzipped Data (INI-Data)
*.inf     Data for identification of drivers (Windows)
*.ini     Initializing Data of a Program
*.isu    Netscape Init-Strings
*.jpe   JPEG-Extended Picture
*.jpg   JPEG-Bild-Data
*.kbd   Keyboard-Modul
*.lda   MS Access system specific information for Tabelles
*.ldb   Init for the  MS Access Databank
*.lex   Lexikon-Data
*.lha   Compress Data in LHA-Format
*.lnk   Shortcut to a Program
*.log   Log file
*.lzh   Compress data in LZH-Format
*.mad   Access Module Shortcut
*.maf   Access Message Shortcut
*.mak   OLE-path instructions for COREL
*.mam  Access Form Shortcut
*.maq   Access request shortcut
*.mat   Access Tabel Shortcut
*.mcc  MSN Calling Program
*.mda   MS Access System specific Tabel
*.mdb   MS Access Databank
*.mdn   Access System Data
*.mdt    Access Add-In Data
*.mdw  Access Workgroups
*.mdz   Access Wizard - Help Data
*.me     Text data (ex. read.me)
*.mff     Midi File Format Sequencer Data
*.mid    MIDI-Sound-Data
*.mod   Saving Protocol
*.mod   MONO-Digitally-Remastered Audio-File
*.mov   Movie (Quicktime-Movie-Format)
*.mpd   SCSI-Port-Init
*.mpg   Video-File to MPEG-Standard
*.ms     Checklist after running a Virus check
*.msg   Network Message
*.msn   MSN Network File
*.msp   Paintbrush Picture in old Format
*.mvs   Info data from ISH Shareware
*.mwf   COREL Move Data
*.nls   Dialer calling Protocol
*.obd   Office 95 mapping Data
*.obt    Office 95 mapping V
*.obz    Office 95 mapping A
*.ofn    Win95 Office Document
*.olb    Object Library (graphic modus)
*.old    Backup copy of  System Data
*.or2   Lotus Organizer 2.x Datei
*.org   Lotus Organizer 1.x Datei
*.ovl    Overlay Keyboard color driver (Dos)
*.pat   COREL Pattern Data
*.pbk   MSN Network Phonebook
*.pct   DOS-Grafic Viewer
*.pcx   Paintbrush Picture
*.pdr   SCSI recognition Modul
*.pfp   Fontographer Font viewing data
*.pif     Program information
*.pot   Office 98 Powerpoint Oresentation form
*.pps  Office 98 Powerpoint Layouts
*.ppt   Powerpoint presentation
*.prf    Normal Color Matching Proof Modul
*.pro   DOS-Display-Modus (depends from Video Card)
*.prt    Print ready Data in MS Schedule +
*.pst   COREL Post-Script-Font
*.pub  COREL Ventura Publication
*.pul   D-Fax/D-Info search criterium/initialization
*.pwl   Symbol or Password Init
*.pwz   Office 98 Powerpoint Assistent
*.qic   Backup-Data von MS BACKUP
*.qtc   Apple Quicktime Video Identification
*.ra     REAL Audio Sound-File
*.ram  REAL Audio Mega Quality Sound-File
*.rc     Netscape News-File
*.rec   Recordermacro
*.reg   Registration editor list
*.rmi   registered MIDI-File (Microsoft)
*.rtf    Rich-Text-Format Text data (readable in Word)
*.scd   MS Schedule + (System data)
*.sch   Schedule +  System data
*.scp   DFÜ-Script Data
*.scr    Screensaver data
*.scr   Script administrative data
*.scz   Copy from Schedule+ System data
*.set    Backup System Data Intern
*.shb   COREL Show Animation
*.shr   Corel Show RUN presentation sequence
*.shs   System intern temporary Data
*.shw   COREL Show File
*.slk     Excel Data Import File
*.snd   Sound File Basic
*.sts    Status after running MEMMAKER
*.swp  Windows 95 Display Data
*.sy_    Not Unzipped System Data
*.syb   BackUp Copy of a *.sys
*.syk   BackUp copie of a *.sys
*.sys   System specific Data
*.sea  Compressed Data (Stuffit Mac)
*.tar   Compressed Data in TA-Format
*.taz   Compressed Data in TA-Format
*.tco   Spea Setup Protokoll
*.tga   Targa Format (Picture Data)
*.thn   Thumbnail (Minia Picture in Grafic Workshop 1.x)
*.tif      Tagged Image Format (Picture Data)
*.tlb     Type Library (ex. COREL )
*.tmp   Temporary Data
*.tpl      MIDI-Template
*.trm    Settings for Terminal program
*.trn     ASCII Code Modul
*.tsk     Task File Description
*.ttf      True Type Fonts
*.txt     Text Data
*.url   Internet Address instruction Data (Uniscoure Resource Locator)
*.vbx   Visual Basic Library
*.vbs   Visual Basic Script
*.vid   Visual Basic Identification Driver
*.voc   Vocal Sound File
*.vue   Validating Password-File (Win 95)
*.vxd   Windows specific Driver
*.w31   BackUp Data to restore Win 3.1
*.w95   Important Windows 95 Backup
*.wav   Wave Audio Data
*.wbk   MS Word Workbench Backup copy
*.wiz     MS Word Wizard Assistent
*.wll      MS Word Add-In
*.wmf   Windows Meta File (Clipart Grafic Data)
*.wpg   DOS Picture
*.wps   Write Personal Script or Text-File
*.wri   Text in Write Format (Word-Pad)
*.wrk   Cakewalk Pro Sequence File
*.wrl   Vrealm 3D World Data
*.xbm   Internet Image (Autoload)
*.xla   Excel Add-In Data
*.xlb   MS Excel Data
*.xlc   Excel Chart (Diagram)
*.xld   Excel Dialog Data
*.xlk   Excel BackUp Copy
*.xll    Excel XLL-Add-In
*.xlm  Excel Macro form
*.xls   Excel Tabel
*.xlt   Excel Template
*.xlv   Excel Visual Basic Modul
*.xlw   Excel Workgroups
 - (Don't know any)
*.zip   Compressed Data

General Extensions
*.$$$   Buffer Data in a Dos Game
*.- - -     Backup Data for Windows 3.x
*.~mp   Duplicate from a Temporary Data
*.000    BackUp from a Windows Program
*.2gr     VGA-Color-Init
*.386    Important System Components, Emulators
*.3gr    VGA-Color-Init