Browse file extensions by file type category:
System file type extensions
(482 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 |
![]() | Dynamic Link Library |
file extension dat | Program data |
![]() | macOS folder information |
file extension sys | System file |
![]() | Microsoft Windows trace log |
![]() | Microsoft Windows Assistance Platform client help document |
![]() | Microsoft Windows 95/98 clipboard data |
file extension so | ELF shared library |
file extension 0 | Linux shared library link |
![]() | MultiLanguage Windows resource data |
file extension rom | Read Only Memory image |
![]() | MS Windows screensaver |
file extension pat | Synology DiskStation DSM update |
file extension rio | IBM AIX system data |
![]() | ReadyBoost cache |
file extension dump | Dump data |
file extension efi | Extensible Firmware Interface |
file extension bzi | Darik's Boot And Nuke kernel data file |
file extension idx | Index file |
![]() | Microsoft Windows prefetch data |
![]() | ActiveX Control |
![]() | Microsoft Source Profiler profiler command |
![]() | Microsoft Security Catalog |
![]() | Windows installation script |
![]() | Microsoft Windows event log |
![]() | Microsoft Windows registry changes temporary data |
Windows sidebar gadget | |
![]() | Windows registry data |
file extension sha | Unix SHAR archive |
![]() | Microsoft Windows 2000/XP mandatory user profile |
![]() | Microsoft Windows 7 registry key file |
![]() | iPod control data file |
![]() | Microsoft Windows device driver |
file extension lock | Lock data |
file extension apdisk | Apple macOS disk information data |
![]() | Microsoft Windows registry data file |
![]() | Microsoft Windows Mobile data |
file extension sfs | Squashfs file archive |
file extension scexe | HP iL02 firmware update |
![]() | Microsoft Windows Task Scheduler task object |
file extension scc | Visual SourceSafe control data |
![]() | Compact Disc File System |
![]() | Software update |
file extension ddz | Adaptec SCO Unix driver image |
file extension x86 | Microsoft Office dynamic link library |
file extension marker | Microsoft Windows 10 system data |
![]() | Microsoft Windows printing spool |
file extension aix | IBM AIX data |
![]() | Microsoft Windows minidump |
file extension 212 | ASUS BIOS update |
file extension location | Microsoft Windows 10 registry data |
file extension mof | Systems Management Server managed object format |
![]() | Interface Builder user interface resources |
![]() | Overlay file |
file extension swp | Swap file |
file extension krm | Kenwood firmware data |
file extension pbd | PowerBuilder dynamic link library |
![]() | Microsoft Windows Update Package |
file extension adups | Google Android data |
![]() | Microsoft Windows NT setup installation data |
file extension 211 | ASUS BIOS update file |
![]() | Microsoft Windows program group |
![]() | Microsoft Windows system file check data |
![]() | Apple Mac strings |
![]() | Windows device driver |
file extension nxp | AdaOS profiling information for one execution file |
![]() | Microsoft Windows Control Panel data |
file extension pid | Unix process ID |
file extension appledouble | Apple AppleDouble resource data |
file extension uxz | IBM Flex CMM update data |
file extension sc | Framework II display driver |
![]() | Microsoft Windows universal printer unidrv minidriver |
file extension ecd | CoCut Plotter printer driver |
file extension tlb | OLE type library |
![]() | Microsoft Windows Driver Foundation data |
file extension bif | Boot information file |
file extension ovi | PC-9801 FM system data |
file extension acct | IBM AIX system data |
file extension bio | OS/2 BIOS file |
file extension mpkg | Meta package |
file extension cdd | Chromeleon device driver |
![]() | Microsoft management console control data |
![]() | Microsoft Windows virtual device driver |
file extension h86 | CP/M data |
file extension qdz | Stratix V device driver |
![]() | macOS (OS X) service application data |
file extension bom | Apple Mac OS X Bill of Materials |
file extension identifier | Microsoft Windows zone identifier data |
file extension mot | Linux load instructions |
file extension im4p | Apple iOS IMG4 payload data |
file extension ko | Linux kernel module |
![]() | Macintosh file data fork |
file extension alx | BlackBerry application loader |
![]() | macOS (OS X) system localization |
![]() | Microsoft Windows Sound System |
file extension lan | Novell NetWare LAN driver |
![]() | Microsoft National Language Support data |
file extension osp | Crystal Semiconductor driver data |
![]() | Windows Vista file related to Assistance Platform (AP) help |
file extension bcd | Microsoft Windows boot configuration |
file extension 100 | Award BIOS Upgrade File version 1.0 |
file extension crmlog | Microsoft Windows CRM log |
![]() | AMI BIOS firmware data |
![]() | Microsoft Windows shadow spooler file |
![]() | Microsoft Windows application log |
![]() | Help file |
file extension kbd | Keyboard script file layout |
file extension rel | Nintendo Wii relocatable module |
![]() | MAC OS resource data |
![]() | MS-DOS 7 data |
file extension dio | iPaq 914c flash data |
![]() | Microsoft Windows Help general index |
file extension mft | Microsoft Windows NTFS master file table |
file extension cb | Microsoft clean boot data |
file extension ar | Linux/Unix command library |
![]() | Windows Server Update Services patch storage file |
![]() | Windows NT registry hive |
![]() | Microsoft Windows Mobile hive |
file extension nxs | AdaOS support module |
![]() | Lotus 1-2-3 display driver data |
file extension bnr | Nintento Wii homebrew data |
file extension ext4 | Fourth extended filesystem |
file extension access | Java access control data |
![]() | Microsoft Windows Explorer folder data |
file extension ddp | OS/2 device driver profile |
file extension 3_dpo | Ralink RT3070 Linux driver |
![]() | Microsoft Windows Help annotation |
![]() | Remote Installation Services client installation wizard |
![]() | Microsoft HyperText template |
![]() | Microsoft Windows 95 browse information |
![]() | Windows 32-bit system driver |
![]() | Microsoft Windows screen driver |
file extension pdr | Windows Port device driver data |
file extension pci | PCI miniport data |
![]() | Spotlight saved search |
file extension mq | Microsoft Windows message data |
![]() | Microsoft Windows 2000 and XP event log |
file extension vgd | VGA CADD display driver |
![]() | macOS system component |
file extension aug | Red Hat Linux shellvars file |
![]() | Microsoft Windows registry hive log |
file extension rwm | Windows Imaging Resource only image |
file extension tmc | Windows trace message control data |
![]() | macOS (OS X) data |
file extension jfs | Linux/Unix Journaling file system |
file extension vmlt | VMLF related data |
file extension bash_history | Bash history data |
![]() | Microsoft Windows XP product activation data |
file extension gzp | Gazelle system page |
![]() | Microsoft Windows custom virtual device driver |
file extension fid | Microsoft Windows index |
file extension eas | OS/2 extended file attributes |
![]() | Media Control Interface command script |
file extension bbfw | iTunes firmware update |
![]() | Microsoft Windows Assistance Platform client help related data |
file extension oem | OEM install data |
![]() | Windows Installer validation module |
file extension documentrevisions-v100 | macOS (OS X) data |
file extension xmo | Adobe Authorware movie driver |
![]() | MS-DOS mouse menu |
file extension nkey | Silicon Graphics Onyx4 data |
![]() | Java JNI library |
file extension tci | MityDSP-L138 / MityDSP-6748 memory modules cache |
file extension seed | Linux preseed data |
![]() | Windows Send To Mail Recipient data |
file extension inp | Sony HD camera system |
![]() | Microsoft Windows prefetch data |
file extension cdm | Novell NetWare disk drivers NPA |
file extension rfw | Rockchip firmware |
![]() | Keyword index - Microsoft Windows Assistance Platform client help related data |
Corel WordPerfect video resource device driver | |
Corel WordPerfect windows printer driver | |
file extension hx1 | Microsoft Windows data |
![]() | Bitmap image |
file extension dwc | Emulex DWC firmware update file format |
file extension lls | Windows system file |
file extension file | AS/400 physical data |
file extension nos | JNOS system data |
file extension p5x | Microsoft Windows system data |
file extension esn | Microsoft Windows XP System32 cache |
![]() | Microsoft Windows Mobile media library |
![]() | Microsoft Windows crash dump data |
file extension tbs | TuneUp style boot screen |
file extension dll_1029 | Microsoft Windows Dynamic Link Library |
![]() | Microsoft Windows network related data |
![]() | Microsoft Windows registry hive log 2 |
![]() | Microsoft Windows XP system32 data |
![]() | iOS ECID SHSH data |
file extension pxe | Linux, Unix network bootable image |
![]() | Send to My Documents |
file extension pr2 | dBase IV printer driver |
![]() | Microsoft Windows Update status data |
file extension ia64 | HP-UX data |
file extension iot | Hitachi Ladder Editor IO comment |
file extension low | PDP-10 low segment of a two-segment program |
![]() | macOS (OS X) system data |
![]() | MS-DOS Shell Monitor data |
file extension srec | Motorola S-Records data |
file extension journal_info_block | Apple Mac filesystem |
file extension install_backup | AVG shell extension module |
![]() | HTML Help table of contents |
file extension ext2 | Linux second extended file system |
file extension htw | Microsoft Windows data |
![]() | Mac Quartz graphics |
![]() | Scap Mac OS X data |
file extension fwl | FileWrangler EXE library |
file extension failurerequests | macOS (OS X) data |
file extension uaq | Microsoft Windows action queue file |
![]() | MS-DOS data |
file extension vcn | NCDrive Vacon NX system software data |
file extension xnc | Modbus Slave XNC driver application |
![]() | OS X (macOS) software update SUCatalog |
file extension dat_tureg_old | Windows Registry data |
![]() | Microsoft Windows heap dump data |
file extension ara | ATI Radeon video driver |
![]() | Mac localized project folder |
file extension bash_profile | Bash interactive login shell |
file extension aql | AOL DLL library |
file extension mui | Amiga MUI default class/library data |
file extension rm7 | Casio registration memory data |
file extension wdr | Psion Series 3 printer driver |
![]() | Microsoft Windows Shell Common DLL file |
file extension pd0 | SonTek firmware |
![]() | Microsoft Windows Performance Monitor report |
file extension ffw | Festo Firmware file |
![]() | Apple Mac kernel extension |
file extension jlb | PAC Mate BX keyboard driver |
![]() | Microsoft PowerToys Explorer tool data |
![]() | MAC OS X file |
file extension apple_partition_map | Apple partition scheme |
file extension idx_dll | Microsoft Office IDX_DLL file |
file extension sdb | Windows Compatibility Solution Database |
file extension spkg | Microsoft Windows Phone driver package |
file extension hhk | Microsoft HTML help index |
file extension lzt | HP StoreEver 1/8 G2 firmware data |
![]() | Apple Mac OS X color picker component |
file extension bada | Samsung bada data |
file extension ubl | DM35x user boot loader data |
file extension vet | VET antivirus system file |
file extension qky | Linux Quirky kernel data |
![]() | Microsoft Windows Server saved DsQuery data |
Microsoft Word for DOS printer driver | |
file extension cgk | BlueSoleil data |
file extension hcd | Huawei system data |
file extension ln | UNIX lint data |
![]() | Microsoft Windows virtual device driver |
file extension zex | ZOOM MRS-802 system data |
file extension hsancillary | Mac OS data |
file extension bsdiff | Cygwin data |
![]() | Mac OS X file system plug-in |
![]() | Sony PlayStation Portable PSP resource file |
file extension trx_dll | Microsoft Office dynamic link library |
file extension nvu | nVidia graphic driver data |
![]() | Autostart CDROM script |
file extension nld | AMD ATI Radeon video driver |
file extension ltn | CD-ROM driver |
file extension grm | Microsoft Windows data |
file extension cgz | Linux drivers archive |
file extension qts | QuickTime system data |
file extension file | macOS (OS X) data |
![]() | MS-DOS pipe |
![]() | Microsoft Windows policy data |
file extension sdb | Custom Application Compatibility Database |
file extension restorelist | Microsoft Windows file system permission |
file extension _dl | Dynamic Link Library DLL file form |
file extension devicemanifest-ms | Microsoft Windows device metadata |
file extension cxn | Conexant driver |
file extension 1092 | Microsoft Windows data |
file extension rbh | RBH Access Technologies firmware |
![]() | bridgesupport Mac OS X file extension |
file extension ham | Novell NetWare disk drivers NPA |
file extension profile | Bash shell profile |
file extension cnv | Microsoft Word text conversion data |
file extension aqm | CP/M information data |
file extension 4fs | Puppy Linux saved state |
![]() | Microsoft Windows Mobile registry entry |
file extension qpr | OS/2 print queue device driver |
![]() | Microsoft Windows directory |
file extension o00 | Always Technology SCSI Controller Driver |
file extension rs | Windows Rating System rating data |
file extension 3gr | Windows Screen Grabber for MS-DOS applications VGA graphics driver |
![]() | Microsoft Windows Internet Naming Service |
file extension cq | SYSGEN replacement data |
file extension n90 | Apple iOS kernel cache |
file extension fstab | File system table |
file extension ~bt | Microsoft Windows update directory |
![]() | Microsoft Windows Assistance Platform client help data |
file extension 2gr | Windows VGA graphic drivers |
file extension doh | Geoworks GEOS dependency information |
file extension wpx | Adobe printer description |
file extension 8xu | Texas Instruments TI-83 Plus operating system data |
![]() | Apple Mac OS X Dashboard widget |
file extension os2 | OS/2 system data |
file extension hxi | Microsoft Help compiled storage file |
![]() | Apple Mac OS X (macOS) index cache |
file extension emm | Expanded memory manager data |
![]() | Win32s data |
file extension crp | MSI SecureDoc encrypted data |
file extension ls_ | Unix ls directory |
file extension equiv | IBM AIX host file |
![]() | Mac ColorSync filter data |
file extension tnr | GPS Pathfinder ProXR/XRS firmware |
file extension lgp | Microsoft Windows application log |
file extension rsq | IBM 4690 Operating System​ data |
![]() | Overlay data |
![]() | Apple Mac display panel plug-in file type |
file extension mpa | Palm memo |
file extension lgx | Microsoft Windows received message data |
![]() | Overlay file |
![]() | Microsoft Windows system data |
![]() | Mac system data |
file extension gr3 | Graphics device driver |
file extension fgdump-log | Microsoft Windows fgdump data |
![]() | Administrator policy template |
![]() | Spotlight importer setting file |
![]() | Windows NT/XP uniqueness database |
![]() | MS-DOS DEBUG input |
file extension dbfseventsd | Mac OS X data |
file extension sty | DirectMusic style data |
file extension int | Sony HD camera system data |
![]() | Adobe AIR data |
![]() | Apple Mac Install Helper document |
file extension 001 | Unix system file |
![]() | Microsoft Windows Assistance Platform task metadata |
file extension grd | Drivers for GRX |
![]() | Apple iTunes iOS firmware update |
file extension nxd | AdaOS debugging information for a module |
file extension migtable | Microsoft Windows data |
file extension _vti_bin | SharePoint data |
file extension efires | Extensible Firmware Interface image |
file extension vfs | Virtual file system index |
file extension sgn | Slax boot file |
file extension xdsl | D-link router UK firmware update |
file extension 3~6 | Microsoft Windows 3.x system data |
![]() | Norton Viewer DLL library |
file extension sf0 | Microsoft Windows sytem file check data |
![]() | Mac OS X Screen Saver |
![]() | Mac Mach kernel extension memory cache |
file extension bud | Microsoft Windows binary printer description |
file extension sfe | Logomatic v2 system data |
![]() | CHKDSK found folder |
file extension cdev | Macintosh II control panel data |
![]() | AppleScript scripting addition data |
file extension nu4 | Norton Utilities DLL root data |
file extension lex | Lex or Flex data |
![]() | Microsoft eXtended Memory specification data |
file extension $$$ | OS/2 operating system file type |
file extension pcm | LaserJet Printer Cartridge Metric for printer driver |
file extension sc | Unix spreadsheet commands |
file extension m$s | MindStor firmware update |
file extension 0 | PSERVER printer queue information data |
![]() | MS-DOS video driver |
file extension afs | FreeBSD data |
file extension n81 | Apple iOS kernel cache |
file extension cpy | Atari Ramdrive CPY commands |
file extension sparc | SunOS 4 data |
file extension rat | Microsoft Windows rating system data |
file extension n90ap | iPhone Jailbreak firmware |
file extension 500 | Linux data |
file extension ox2 | Orangutan X2 firmware update |
file extension b | LILO Boot Loader image |
![]() | Windows 3.x swap file |
![]() | Mac OS X System Preference Pane app |
file extension cpi | Microsoft MS-DOS code page information |
![]() | Visual FoxPro dynamic link library |
file extension sl | HP-UX shared library |
file extension acv | OS/2 audio driver |
file extension 3fs | Puppy Linux saved state |
file extension ds | Desktop Korn Shell data |
file extension ecw | System dll library |
file extension 120 | Award BIOS upgrade file |
file extension dvd | MS-DOS hardware device driver |
![]() | 4DOS description |
file extension vxx | IOsubsys drive data |
file extension riscos | Acorn RISC OS data |
![]() | Screensaver |
file extension pid | Creative Labs driver |
file extension mva | Matrox video card driver |
file extension dpb | Microsoft Windows driver related data |
![]() | Systems Management Server software inventory |
file extension w20 | Windows 2000 system data |
![]() | Apple Quick Look plug-in |
file extension xxt | Dynamic Link Library |
![]() | Microsoft Profiler output |
file extension fx | DirectX D3DXEffect object |
file extension sdr | QuickView Pro for DOS soundcard driver |
![]() | Microsoft Windows OpenGL installable client driver |
![]() | Microsoft Windows kernel module |
file extension dan | AMD ATI Radeon video driver |
file extension aad | FreeBSD package |
![]() | Apple Mac OS system driver |
file extension dlm | Dynamic Link module |
![]() | MS-DOS implementing support for Windows DLL's |
file extension mcp | Amiga MUI preference class or library |
file extension mojito | Limewire Kademlia data |
file extension macs | Apple Mac OS system data |
file extension dis | Soundweb firmware update |
file extension osinstallmessages | macOS system data |
file extension do7 | MS-DOS 7 data |
file extension dmd | OS/2 Warp device manager driver |
![]() | Mac OS X System Profiler Reporter file |
file extension ifs | IBM OS/2 installable file system data |
![]() | Overlay file |
file extension dvc | LoseThos partition drive file |
file extension mps_ | MPW Shell data |
![]() | Microsoft Windows system32 data |
![]() | Microsoft Windows multilingual user interface data |
![]() | Overlay file |
file extension dir | Directory indicator |
![]() | Masked Dynamic Link Library |
file extension cmg | cramfs ROM file system package |
file extension ftg | Microsoft Windows Help data |
file extension hpfs | OS/2 High Performance File System |
file extension k48 | Apple iOS kernel cache |
![]() | Microsoft Windows data |
file extension kmd | Clicker module output |
file extension scsi | Apple HDD setup data |
file extension b~k | Microsoft Windows 3.x data |
![]() | ProDOS 16 or GS/OS shell application |
file extension apd | IBM Lotus printer driver |
![]() | Overlay file |
![]() | OS X Mach Kernel system data |
file extension group | Linux system data |
file extension atahd | Puppy Linux ATA hard drive flag |
file extension add | Adapter device driver file |
file extension asd | Lotus screen driver |
Corel WordPerfect driver data | |
file extension rdl | Symbian recogniser library |
file extension exopc | ExoPC application data |
![]() | MacOS system data |
![]() | macOS system data |
file extension 2sf | Puppy Linux data |
file extension aa | Unix data |
![]() | Apple MAC OS X console query |
file extension pdl | Symbian OS printer driver |
file extension hlx | ATI Radeon video driver |
file extension kss | KDE screen saver |
file extension nst | Nokia Star Torrent system data |
file extension dsk | Novell NetWare disk driver |
file extension scd | Systems Management Server (SMS) site control file deletion |
file extension nu6 | Norton Utility system dll library |
file extension cachedump | Microsoft Windows system data |
file extension sf | OS/2 work place shell attribute storage |
file extension flg | Puppy Linux partition flag |
file extension upd | HP universal print driver |
file extension fs | NetBSD system data |
![]() | PEN Windows device definition file |
file extension rdz | Mandrake Linux install file |
file extension rtb | NAT proxy servers file |
file extension aws | ActiveWords System file |
file extension que | PDP-10 queue data |
file extension not_terminated | Mac OS X audit log |
![]() | NetWare 2 value added process file |
![]() | Microsoft Windows workspace configuration |
file extension cin | OS/2 change control file |
file extension plt | EPOC software platform data |
file extension ali | BeOS ALI ata |
file extension env | HP-95 environment data |
file extension hpc | System dynamic library file |
file extension bsd | FacetWin bitwise backup set file |
file extension plk | AMD ATI Radeon video driver |
file extension chs | Microsoft Windows Chinese noise-word list |
file extension dsp | Dr.Halo graphics display driver |
file extension ioplist | Apple Mac OS X ioplist file |
file extension adv | Gravis Ultrasound virtual device driver file |
file extension dif | OS/2 display information file |
file extension qcc | Niobrata QUCM firmware |
file extension cht | Microsoft Windows Chinese noise-word list file |
file extension rpp | Symbian OS pre-processed resource |
![]() | Mac OS X system file |
file extension cnm | Microsoft Windows application menu options and setup file |
file extension fin | AMD ATI Radeon video driver |
![]() | Novell Netware loadable module file |
![]() | le Mac OS X file |
file extension flt | OS/2 warp filter device driver file |
file extension irix6 | Irix 6 file |
file extension irc | Nevo Infra-Red device code file format |
file extension novs | Novell NetWare Control Center file |
file extension sdev | Apple System 7 Control Strip module |
![]() | Internet preference file |
file extension ril | Google Android radio interface library |
file extension ad | UNIX application default resource file |
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