System File Types - File extensions used for system files.
| Extension | File Description | Popularity | |
| .386 | Windows Virtual Device Driver | Rare | |
| .8xu | TI-83 Plus Operating System File | Uncommon | |
| .adm | Administrative Template File | Average | |
| .ani | Windows Animated Cursor | Average | |
| .ann | Help Annotations | Average | |
| .aos | ARCHOS PCtablet Firmware File | Uncommon | |
| .bio | BIOS File | Uncommon | |
| .bmk | Help Bookmarks | Average | |
| .bom | Mac OS X Bill of Materials File | Uncommon | |
| .cab | Windows Cabinet File | Very Common | |
| .cgz | Linux Drivers Archive | Average | |
| .clb | COM+ Catalog File | Average | |
| .cnt | Help Contents File | Average | |
| .cpi | Codepage Information File | Average | |
| .cpl | Windows Control Panel | Very Common | |
| .crash | Mac OS X Crash Log File | Average | |
| .cur | Windows Cursor | Very Common | |
| .desklink | Desktop Shortcut | Average | |
| .dev | Windows Device Driver File | Average | |
| .dll | Dynamic Link Library | Very Common | |
| .dmp | Windows Memory Dump | Very Common | |
| .drv | Device Driver | Very Common | |
| .dss | DCC Active Designer File | Average | |
| .dvd | DOS Device Driver | Average | |
| .emerald | Emerald Theme | Uncommon | |
| .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 | Common | |
| .ftg | Full Text Group | Average | |
| .fts | Full Text Search | Average | |
| .grl | Windows Update Status File | Rare | |
| .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 | Common | |
| .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 | |
| .ko | Linux Kernel Module File | Average | |
| .lnk | File Shortcut | Very Common | |
| .log1 | Windows Registry Hive Log File | Average | |
| .log2 | Windows Registry Hive Log 2 File | Average | |
| .manifest | Windows Visual Styles File | Average | |
| .mapimail | Send To Mail Recipient | Average | |
| .mdmp | Windows Minidump | Average | |
| .metadata_never_index | Spotlight Never Index File | Uncommon | |
| .mi4 | Audio Player Firmware File | Average | |
| .msc | Microsoft Management Console Snap-in Control File | Average | |
| .msp | Windows Installer Patch | Average | |
| .msstyle | Windows XP Unsigned Style | Uncommon | |
| .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 | |
| .panic | Kernel Panic File | Uncommon | |
| .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 | |
| .qvm | Q Virtual Machine | Rare | |
| .reg | Registry File | Average | |
| .rmt | Router Firmware File | Average | |
| .ruf | Samsung DVD and Blu-ray Player Firmware File | Rare | |
| .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 | |
| .xrm-ms | Microsoft Security Certificate | Uncommon |
Posts
