Browse file extensions by file type category:
System file type extensions
(481 file extension database entries)
File extensions used for computer operating systems internal use and which are required for proper and healthy functionality of any operating system
System file extension list
File extensions used for computer operating systems internal use and which are required for proper and healthy functionality of any operating system.
System files are very important group of file formats, which are used by computer operating systems. If any of these files are missing or corrupted, the operating system usually doesn't work correctly or doesn't start at all. Many system files have their file attribute set to hidden, so they aren't visible to users, as a preventive measures . Basic system files are incompatible between various operating systems and each operating system has its own native binary formats for them. For example Microsoft Windows system files could never work as system files for Linux or MAC OS X.
Device drives are a bit of exception. Microsoft Windows device drivers are still not compatible with Linux or MAC OS X, but the same driver could possibly be used in different versions of Microsoft Windows, e.g. Windows 95/98/Me have the same driver file format, and often drivers for Windows 95 could work in the newer Windows Me.
Most widely used system file extensions are sys, drv, dll, inf etc..
More experienced users can configure Windows Explorer or file manager to show hidden and system files. But be very careful, any damage to important system files can lead to malfunction or an unstable operating system.
Sort by: Extension![]() | Sort by: File type description |
file extension ~bt | Microsoft Windows update directory |
file extension _vti_bin | SharePoint data |
![]() | iPod control data file |
file extension _dl | Dynamic Link Library DLL file form |
file extension zex | ZOOM MRS-802 system data |
file extension xxt | Dynamic Link Library |
file extension xnc | Modbus Slave XNC driver application |
![]() | Microsoft eXtended Memory specification data |
file extension xmo | Adobe Authorware movie driver |
file extension xdsl | D-link router UK firmware update |
file extension x86 | Microsoft Office dynamic link library |
![]() | Microsoft Windows Sound System |
Corel WordPerfect windows printer driver | |
file extension wpx | Adobe printer description |
![]() | Windows 3.x swap file |
file extension wdr | Psion Series 3 printer driver |
![]() | Apple Mac OS X Dashboard widget |
![]() | Microsoft Windows Driver Foundation data |
![]() | Microsoft Windows workspace configuration |
file extension w20 | Windows 2000 system data |
file extension vxx | IOsubsys drive data |
![]() | Microsoft Windows virtual device driver |
![]() | Microsoft Windows custom virtual device driver |
Corel WordPerfect video resource device driver | |
file extension vmlt | VMLF related data |
![]() | MS-DOS video driver |
file extension vgd | VGA CADD display driver |
![]() | Bitmap image |
file extension vfs | Virtual file system index |
file extension vet | VET antivirus system file |
![]() | Windows 32-bit system driver |
file extension vcn | NCDrive Vacon NX system software data |
![]() | NetWare 2 value added process file |
file extension uxz | IBM Flex CMM update data |
file extension upd | HP universal print driver |
![]() | Windows NT/XP uniqueness database |
![]() | Microsoft Windows XP system32 data |
file extension ubl | DM35x user boot loader data |
file extension uaq | Microsoft Windows action queue file |
![]() | Microsoft Windows system32 data |
file extension trx_dll | Microsoft Office dynamic link library |
file extension tnr | GPS Pathfinder ProXR/XRS firmware |
file extension tmc | Windows trace message control data |
file extension tlb | OLE type library |
![]() | Microsoft Windows Shell Common DLL file |
file extension tci | MityDSP-L138 / MityDSP-6748 memory modules cache |
file extension tbs | TuneUp style boot screen |
![]() | macOS (OS X) system data |
file extension sys | System file |
file extension swp | Swap file |
![]() | MAC OS X file |
![]() | OS X (macOS) software update SUCatalog |
file extension sty | DirectMusic style data |
![]() | Apple Mac strings |
![]() | Screensaver |
file extension srec | Motorola S-Records data |
![]() | Mac OS X System Profiler Reporter file |
![]() | Microsoft Windows printing spool |
file extension spkg | Microsoft Windows Phone driver package |
file extension sparc | SunOS 4 data |
file extension so | ELF shared library |
file extension sl | HP-UX shared library |
![]() | Microsoft Windows NT setup installation data |
![]() | Systems Management Server software inventory |
![]() | iOS ECID SHSH data |
![]() | Microsoft Windows 95/98 clipboard data |
![]() | MacOS system data |
![]() | Microsoft Windows shadow spooler file |
file extension sha | Unix SHAR archive |
file extension sgn | Slax boot file |
file extension sfs | Squashfs file archive |
file extension sfe | Logomatic v2 system data |
![]() | ReadyBoost cache |
![]() | Microsoft Windows system file check data |
file extension sf0 | Microsoft Windows sytem file check data |
file extension sf | OS/2 work place shell attribute storage |
![]() | macOS (OS X) service application data |
file extension seed | Linux preseed data |
![]() | Apple Mac OS X (macOS) index cache |
file extension sdr | QuickView Pro for DOS soundcard driver |
file extension sdev | Apple System 7 Control Strip module |
file extension sdb | Custom Application Compatibility Database |
file extension sdb | Windows Compatibility Solution Database |
file extension scsi | Apple HDD setup data |
![]() | MS Windows screensaver |
![]() | MS-DOS DEBUG input |
file extension scexe | HP iL02 firmware update |
file extension scd | Systems Management Server (SMS) site control file deletion |
file extension scc | Visual SourceSafe control data |
![]() | Scap Mac OS X data |
file extension sc | Framework II display driver |
![]() | Mac OS X Screen Saver |
![]() | Spotlight saved search |
![]() | MS-DOS 7 data |
file extension rwm | Windows Imaging Resource only image |
![]() | Software update |
file extension rtb | NAT proxy servers file |
![]() | MAC OS resource data |
file extension rsq | IBM 4690 Operating System​ data |
file extension rs | Windows Rating System rating data |
file extension rpp | Symbian OS pre-processed resource |
file extension rom | Read Only Memory image |
file extension rm7 | Casio registration memory data |
file extension riscos | Acorn RISC OS data |
file extension rio | IBM AIX system data |
file extension ril | Google Android radio interface library |
![]() | Microsoft Windows Mobile registry entry |
file extension rfw | Rockchip firmware |
file extension restorelist | Microsoft Windows file system permission |
file extension rel | Nintendo Wii relocatable module |
![]() | Microsoft Windows registry changes temporary data |
![]() | Windows registry data |
file extension rdz | Mandrake Linux install file |
file extension rdl | Symbian recogniser library |
![]() | Sony PlayStation Portable PSP resource file |
file extension rbh | RBH Access Technologies firmware |
file extension rat | Microsoft Windows rating system data |
![]() | Mac OS X system file |
file extension que | PDP-10 queue data |
![]() | Mac Quartz graphics |
file extension qts | QuickTime system data |
file extension qpr | OS/2 print queue device driver |
![]() | Apple Quick Look plug-in |
file extension qky | Linux Quirky kernel data |
![]() | Mac ColorSync filter data |
file extension qdz | Stratix V device driver |
![]() | Microsoft Windows Server saved DsQuery data |
file extension qcc | Niobrata QUCM firmware |
file extension pxe | Linux, Unix network bootable image |
![]() | Windows Server Update Services patch storage file |
![]() | Microsoft Windows directory |
![]() | Norton Viewer DLL library |
file extension profile | Bash shell profile |
![]() | Microsoft Profiler output |
![]() | Mac OS X System Preference Pane app |
Microsoft Word for DOS printer driver | |
file extension pr2 | dBase IV printer driver |
![]() | Microsoft Windows policy data |
![]() | Microsoft Windows Performance Monitor report |
file extension plt | EPOC software platform data |
file extension plk | AMD ATI Radeon video driver |
file extension pid | Unix process ID |
file extension pid | Creative Labs driver |
![]() | Microsoft Windows prefetch data |
file extension pdr | Windows Port device driver data |
file extension pdl | Symbian OS printer driver |
file extension pd0 | SonTek firmware |
file extension pcm | LaserJet Printer Cartridge Metric for printer driver |
file extension pci | PCI miniport data |
![]() | Microsoft Source Profiler profiler command |
file extension pbd | PowerBuilder dynamic link library |
![]() | Microsoft Windows Mobile data |
file extension pat | Synology DiskStation DSM update |
file extension p5x | Microsoft Windows system data |
file extension ox2 | Orangutan X2 firmware update |
![]() | Overlay file |
file extension ovi | PC-9801 FM system data |
![]() | Overlay file |
![]() | Overlay data |
![]() | Overlay file |
![]() | Overlay file |
![]() | Overlay file |
![]() | Microsoft PowerToys Explorer tool data |
file extension osp | Crystal Semiconductor driver data |
file extension osinstallmessages | macOS system data |
![]() | Remote Installation Services client installation wizard |
![]() | AppleScript scripting addition data |
file extension os2 | OS/2 system data |
file extension oem | OEM install data |
![]() | ActiveX Control |
file extension o00 | Always Technology SCSI Controller Driver |
file extension nxs | AdaOS support module |
file extension nxp | AdaOS profiling information for one execution file |
file extension nxd | AdaOS debugging information for a module |
file extension nvu | nVidia graphic driver data |
file extension nu6 | Norton Utility system dll library |
file extension nu4 | Norton Utilities DLL root data |
file extension nst | Nokia Star Torrent system data |
file extension novs | Novell NetWare Control Center file |
file extension not_terminated | Mac OS X audit log |
file extension nos | JNOS system data |
![]() | Microsoft National Language Support data |
![]() | Novell Netware loadable module file |
file extension nld | AMD ATI Radeon video driver |
file extension nkey | Silicon Graphics Onyx4 data |
![]() | Adobe AIR data |
![]() | Interface Builder user interface resources |
![]() | Apple Mac OS system driver |
file extension n90ap | iPhone Jailbreak firmware |
file extension n90 | Apple iOS kernel cache |
file extension n81 | Apple iOS kernel cache |
![]() | Send to My Documents |
file extension mva | Matrox video card driver |
![]() | Microsoft Windows Update Package |
![]() | Microsoft Windows multilingual user interface data |
![]() | MultiLanguage Windows resource data |
file extension mui | Amiga MUI default class/library data |
![]() | Microsoft Windows network related data |
![]() | Microsoft Windows system data |
![]() | Microsoft management console control data |
file extension mq | Microsoft Windows message data |
file extension mps_ | MPW Shell data |
file extension mpkg | Meta package |
file extension mpa | Palm memo |
file extension mot | Linux load instructions |
![]() | Apple Mac display panel plug-in file type |
file extension mojito | Limewire Kademlia data |
file extension mof | Systems Management Server managed object format |
![]() | MS-DOS implementing support for Windows DLL's |
![]() | Microsoft Windows kernel module |
![]() | PEN Windows device definition file |
![]() | MS-DOS mouse menu |
![]() | Microsoft Windows Mobile media library |
![]() | Mac Mach kernel extension memory cache |
file extension migtable | Microsoft Windows data |
file extension mft | Microsoft Windows NTFS master file table |
![]() | Microsoft Windows minidump |
![]() | Spotlight importer setting file |
file extension mcp | Amiga MUI preference class or library |
![]() | Media Control Interface command script |
file extension marker | Microsoft Windows 10 system data |
![]() | Windows Send To Mail Recipient data |
![]() | Microsoft Windows 2000/XP mandatory user profile |
file extension macs | Apple Mac OS system data |
file extension m$s | MindStor firmware update |
file extension lzt | HP StoreEver 1/8 G2 firmware data |
file extension ltn | CD-ROM driver |
file extension ls_ | Unix ls directory |
![]() | Mac localized project folder |
file extension low | PDP-10 low segment of a two-segment program |
![]() | Microsoft Windows registry hive log 2 |
![]() | Microsoft Windows registry hive log |
file extension lock | Lock data |
file extension location | Microsoft Windows 10 registry data |
![]() | macOS (OS X) system localization |
file extension ln | UNIX lint data |
file extension lls | Windows system file |
file extension lgx | Microsoft Windows received message data |
![]() | Microsoft Windows application log |
file extension lgp | Microsoft Windows application log |
file extension lex | Lex or Flex data |
![]() | le Mac OS X file |
![]() | Lotus 1-2-3 display driver data |
file extension lan | Novell NetWare LAN driver |
file extension kss | KDE screen saver |
file extension krm | Kenwood firmware data |
file extension ko | Linux kernel module |
file extension kmd | Clicker module output |
![]() | Microsoft Windows 7 registry key file |
![]() | Apple Mac kernel extension |
![]() | Microsoft Windows crash dump data |
file extension kbd | Keyboard script file layout |
file extension k48 | Apple iOS kernel cache |
file extension journal_info_block | Apple Mac filesystem |
![]() | Microsoft Windows Task Scheduler task object |
![]() | Java JNI library |
file extension jlb | PAC Mate BX keyboard driver |
file extension jfs | Linux/Unix Journaling file system |
![]() | Apple iTunes iOS firmware update |
file extension irix6 | Irix 6 file |
file extension irc | Nevo Infra-Red device code file format |
file extension iot | Hitachi Ladder Editor IO comment |
file extension ioplist | Apple Mac OS X ioplist file |
![]() | 4DOS description |
file extension int | Sony HD camera system data |
file extension install_backup | AVG shell extension module |
![]() | Apple Mac Install Helper document |
![]() | Microsoft Windows Internet Naming Service |
file extension inp | Sony HD camera system |
![]() | Autostart CDROM script |
![]() | Windows installation script |
![]() | MS-DOS data |
file extension im4p | Apple iOS IMG4 payload data |
file extension ifs | IBM OS/2 installable file system data |
file extension idx_dll | Microsoft Office IDX_DLL file |
file extension idx | Index file |
file extension identifier | Microsoft Windows zone identifier data |
![]() | Microsoft Windows OpenGL installable client driver |
![]() | Internet preference file |
file extension ia64 | HP-UX data |
file extension hxi | Microsoft Help compiled storage file |
file extension hx1 | Microsoft Windows data |
![]() | Microsoft Windows Mobile hive |
file extension htw | Microsoft Windows data |
![]() | Microsoft HyperText template |
file extension hsancillary | Mac OS data |
file extension hpfs | OS/2 High Performance File System |
file extension hpc | System dynamic library file |
file extension hlx | ATI Radeon video driver |
![]() | Help file |
![]() | Windows NT registry hive |
file extension hhk | Microsoft HTML help index |
![]() | HTML Help table of contents |
![]() | Microsoft Windows heap dump data |
file extension hcd | Huawei system data |
file extension ham | Novell NetWare disk drivers NPA |
file extension h86 | CP/M data |
![]() | Microsoft Windows Assistance Platform task metadata |
![]() | Microsoft Windows Assistance Platform client help related data |
![]() | Microsoft Windows Assistance Platform client help document |
![]() | Keyword index - Microsoft Windows Assistance Platform client help related data |
![]() | Microsoft Windows Assistance Platform client help data |
![]() | Windows Vista file related to Assistance Platform (AP) help |
file extension gzp | Gazelle system page |
![]() | Microsoft Windows program group |
file extension group | Linux system data |
file extension grm | Microsoft Windows data |
![]() | Microsoft Windows Update status data |
file extension grd | Drivers for GRX |
![]() | MS-DOS Shell Monitor data |
file extension gr3 | Graphics device driver |
![]() | Microsoft Windows screen driver |
![]() | Microsoft Windows universal printer unidrv minidriver |
![]() | Microsoft Windows Help general index |
Windows sidebar gadget | |
file extension fx | DirectX D3DXEffect object |
![]() | Microsoft Windows prefetch data |
file extension fwl | FileWrangler EXE library |
file extension ftg | Microsoft Windows Help data |
file extension fstab | File system table |
![]() | macOS (OS X) data |
file extension fs | NetBSD system data |
![]() | Mac OS X file system plug-in |
![]() | Microsoft Windows Explorer folder data |
file extension flt | OS/2 warp filter device driver file |
![]() | Visual FoxPro dynamic link library |
file extension flg | Puppy Linux partition flag |
file extension fin | AMD ATI Radeon video driver |
file extension file | AS/400 physical data |
file extension file | macOS (OS X) data |
file extension fid | Microsoft Windows index |
file extension fgdump-log | Microsoft Windows fgdump data |
file extension ffw | Festo Firmware file |
file extension failurerequests | macOS (OS X) data |
file extension ext4 | Fourth extended filesystem |
file extension ext2 | Linux second extended file system |
file extension exopc | ExoPC application data |
![]() | Microsoft Windows event log |
![]() | Microsoft Windows 2000 and XP event log |
![]() | Microsoft Windows trace log |
file extension esn | Microsoft Windows XP System32 cache |
file extension equiv | IBM AIX host file |
file extension env | HP-95 environment data |
file extension emm | Expanded memory manager data |
file extension efires | Extensible Firmware Interface image |
file extension efi | Extensible Firmware Interface |
file extension ecw | System dll library |
file extension ecd | CoCut Plotter printer driver |
file extension eas | OS/2 extended file attributes |
file extension dwc | Emulex DWC firmware update file format |
file extension dvd | MS-DOS hardware device driver |
file extension dvc | LoseThos partition drive file |
file extension dump | Dump data |
![]() | Macintosh file data fork |
![]() | macOS folder information |
Corel WordPerfect driver data | |
file extension dsp | Dr.Halo graphics display driver |
file extension dsk | Novell NetWare disk driver |
file extension ds | Desktop Korn Shell data |
![]() | Microsoft Windows device driver |
file extension dpb | Microsoft Windows driver related data |
file extension doh | Geoworks GEOS dependency information |
file extension documentrevisions-v100 | macOS (OS X) data |
file extension do7 | MS-DOS 7 data |
file extension dmd | OS/2 Warp device manager driver |
file extension dlm | Dynamic Link module |
file extension dll_1029 | Microsoft Windows Dynamic Link Library |
![]() | Dynamic Link Library |
![]() | Masked Dynamic Link Library |
file extension dis | Soundweb firmware update |
file extension dir | Directory indicator |
file extension dio | iPaq 914c flash data |
file extension dif | OS/2 display information file |
file extension devicemanifest-ms | Microsoft Windows device metadata |
![]() | Windows device driver |
file extension ddz | Adaptec SCO Unix driver image |
file extension ddp | OS/2 device driver profile |
![]() | Microsoft Windows XP product activation data |
file extension dbfseventsd | Mac OS X data |
file extension dat_tureg_old | Windows Registry data |
file extension dat | Program data |
file extension dan | AMD ATI Radeon video driver |
file extension cxn | Conexant driver |
![]() | Windows Installer validation module |
![]() | OS X Mach Kernel system data |
file extension crp | MSI SecureDoc encrypted data |
file extension crmlog | Microsoft Windows CRM log |
file extension cq | SYSGEN replacement data |
file extension cpy | Atari Ramdrive CPY commands |
![]() | Microsoft Windows Control Panel data |
file extension cpi | Microsoft MS-DOS code page information |
![]() | macOS system data |
![]() | macOS system component |
![]() | Apple Mac OS X color picker component |
file extension cnv | Microsoft Word text conversion data |
file extension cnm | Microsoft Windows application menu options and setup file |
file extension cmg | cramfs ROM file system package |
file extension cin | OS/2 change control file |
file extension cht | Microsoft Windows Chinese noise-word list file |
file extension chs | Microsoft Windows Chinese noise-word list |
file extension cgz | Linux drivers archive |
file extension cgk | BlueSoleil data |
file extension cdm | Novell NetWare disk drivers NPA |
![]() | Compact Disc File System |
file extension cdev | Macintosh II control panel data |
file extension cdd | Chromeleon device driver |
file extension cb | Microsoft clean boot data |
![]() | Microsoft Security Catalog |
file extension cachedump | Microsoft Windows system data |
file extension b~k | Microsoft Windows 3.x data |
file extension bzi | Darik's Boot And Nuke kernel data file |
file extension bud | Microsoft Windows binary printer description |
file extension bsdiff | Cygwin data |
file extension bsd | FacetWin bitwise backup set file |
![]() | bridgesupport Mac OS X file extension |
![]() | Mac system data |
file extension bom | Apple Mac OS X Bill of Materials |
file extension bnr | Nintento Wii homebrew data |
![]() | Microsoft Windows registry data file |
file extension bio | OS/2 BIOS file |
file extension bif | Boot information file |
![]() | Microsoft Windows 95 browse information |
file extension bcd | Microsoft Windows boot configuration |
file extension bbfw | iTunes firmware update |
file extension bash_profile | Bash interactive login shell |
file extension bash_history | Bash history data |
file extension bada | Samsung bada data |
file extension b | LILO Boot Loader image |
file extension aws | ActiveWords System file |
file extension aug | Red Hat Linux shellvars file |
file extension atahd | Puppy Linux ATA hard drive flag |
![]() | Apple MAC OS X console query |
file extension asd | Lotus screen driver |
file extension ara | ATI Radeon video driver |
file extension ar | Linux/Unix command library |
file extension aqm | CP/M information data |
file extension aql | AOL DLL library |
file extension apple_partition_map | Apple partition scheme |
file extension appledouble | Apple AppleDouble resource data |
file extension apdisk | Apple macOS disk information data |
file extension apd | IBM Lotus printer driver |
![]() | Microsoft Windows Help annotation |
![]() | AMI BIOS firmware data |
file extension alx | BlackBerry application loader |
file extension ali | BeOS ALI ata |
file extension aix | IBM AIX data |
file extension afs | FreeBSD data |
file extension adv | Gravis Ultrasound virtual device driver file |
file extension adups | Google Android data |
![]() | Administrator policy template |
file extension add | Adapter device driver file |
file extension ad | UNIX application default resource file |
file extension acv | OS/2 audio driver |
file extension acct | IBM AIX system data |
file extension access | Java access control data |
file extension aad | FreeBSD package |
file extension aa | Unix data |
file extension 8xu | Texas Instruments TI-83 Plus operating system data |
file extension 500 | Linux data |
file extension 4fs | Puppy Linux saved state |
file extension 3~6 | Microsoft Windows 3.x system data |
file extension 3_dpo | Ralink RT3070 Linux driver |
file extension 3gr | Windows Screen Grabber for MS-DOS applications VGA graphics driver |
file extension 3fs | Puppy Linux saved state |
![]() | Win32s data |
file extension 2sf | Puppy Linux data |
file extension 2gr | Windows VGA graphic drivers |
![]() | Microsoft Windows virtual device driver |
file extension 212 | ASUS BIOS update |
file extension 211 | ASUS BIOS update file |
![]() | Microsoft Windows data |
file extension 120 | Award BIOS upgrade file |
file extension 1092 | Microsoft Windows data |
file extension 100 | Award BIOS Upgrade File version 1.0 |
file extension 001 | Unix system file |
![]() | CHKDSK found folder |
file extension 0 | PSERVER printer queue information data |
file extension 0 | Linux shared library link |
![]() | ProDOS 16 or GS/OS shell application |
![]() | MS-DOS pipe |
file extension $$$ | OS/2 operating system file type |