System file types and extensions

Extension File Description   Popularity
.adm Administrative Template File Average
.ani Windows Animated Cursor Average
.ann Help Annotations Average
.bmk Help Bookmarks Average
.cab Windows Cabinet File Very Common
.cgz Linux Drivers Archive Average
.cnt Help Contents File Average
.cpi Codepage Information File Average
.cpl Windows Control Panel Very Common
.cur Windows Cursor Very Common
.desklink Desktop Shortcut Average
.dev Windows Device Driver File Average
.dmp Windows Memory Dump Very Common
.drv Device Driver Very Common
.dss DCC Active Designer File Average
.dvd DOS Device Driver Average
.ffa Find Fast Status File Uncommon
.ffl Find Fast Document List Uncommon
.ffo Find Fast Document Properties Cache Uncommon
.ffx Microsoft Find Fast Index Average
.fpbf Mac OS X Burn Folder Average
.ftg Full Text Group Average
.fts Full Text Search Average
.grp Windows Program Manager Group Average
.hdmp Windows Heap Dump Average
.hhc HTML Help Table of Contents Average
.hhk HTML Help Index Average
.hlp Windows Help File Average
.hpj Help Project File Average
.htt Hypertext Template File Average
.icl Windows Icon Library File Average
.icns Mac OS X Icon Resource File Average
.ico Icon File Common
.idx Index File Average
.ins Internet Naming Service File Average
.ion 4DOS File Description Average
.its Internet Document Set Average
.kbd Keyboard Layout Script Average
.kext Mac OS X Kernel Extension Average
.key Security Key Very Common
.lnk File Shortcut Very Common
.manifest Windows Visual Styles File Average
.mapimail Send To Mail Recipient Average
.mdmp Windows Minidump Average
.msc Microsoft Management Console Snap-in Control File Average
.msp Windows Installer Patch Average
.msstyles Windows XP Style Average
.mui MultiLanguage Resource File Average
.mum Windows Vista Update Package Average
.mydocs Send To My Documents Average
.nfo System Information File Average
.nt Windows NT Startup File Average
.p7b PKCS #7 Certificate File Average
.pdr Windows Port Driver Average
.pfx PKCS #12 Certificate File Average
.pid Creative Driver File Average
.pk2 Silkroad Online Game Data File Average
.pol Windows Policy File Average
.ppd PostScript Printer Description File Average
.prefpane Mac OS X System Preference Pane Average
.prf Windows System File Common
.prt Printer Driver File Average
.pwl Windows Password List Average
.reg Registry File Average
.savedsearch Spotlight Saved Search Average
.saver Mac OS X Screen Saver Average
.scf Windows Explorer Command Common
.scr Windows Screensaver Average
.sdb Custom Application Compatibility Database Uncommon
.str Windows Screensaver File Rare
.swp Swap File Average
.sys Windows System File Very Common
.sys Motorola Driver File Average
.theme Microsoft Plus! Desktop Theme Average
.vga VGA Display Driver Average
.vgd Generic CADD VGA Driver Average
.vxd Virtual Device Driver Average
.wdgt Dashboard Widget Average
.wer Windows Error Report Uncommon
.wpx Printer Description File Average