System file extensions list

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

List of common system file types

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 dll	Dynamic Link Library
file extension dat	Program data
file extension ds_store	macOS folder information
file extension sys	System file
file extension h1s	Microsoft Windows Assistance Platform client help document
file extension etl	Microsoft Windows trace log
file extension shs	Microsoft Windows 95/98 clipboard data
file extension so	ELF shared library
file extension mui	MultiLanguage Windows resource data
file extension 0	Linux shared library link
file extension rom	Read Only Memory image
file extension pat	Synology DiskStation DSM update
file extension bzi	Darik's Boot And Nuke kernel data file
file extension dump	Dump data
file extension rio	IBM AIX system data
file extension scr	MS Windows screensaver
file extension idx	Index file
file extension sfcache	ReadyBoost cache
file extension pf	Microsoft Windows prefetch data
file extension pcf	Microsoft Source Profiler profiler command
file extension regtrans-ms	Microsoft Windows registry changes temporary data
file extension inf	Windows installation script
file extension cat	Microsoft Security Catalog
file extension gadget	Windows sidebar gadget
file extension ocx	ActiveX Control
file extension efi	Extensible Firmware Interface
file extension apdisk	Apple macOS disk information data
file extension evtx	Microsoft Windows event log
file extension _ipod_control	iPod control data file
file extension reg	Windows registry data
file extension man	Microsoft Windows 2000/XP mandatory user profile
file extension key	Microsoft Windows 7 registry key file
file extension scexe	HP iL02 firmware update
file extension payload	Microsoft Windows Mobile data
file extension lock	Lock data
file extension cdfs	Compact Disc File System
file extension blf	Microsoft Windows registry data file
file extension sha	Unix SHAR archive
file extension drv	Microsoft Windows device driver
file extension job	Microsoft Windows Task Scheduler task object
file extension ddz	Adaptec SCO Unix driver image
file extension scc	Visual SourceSafe control data
file extension sfs	Squashfs file archive
file extension x86	Microsoft Office dynamic link library
file extension marker	Microsoft Windows 10 system data
file extension rtp	Software update
file extension 212	ASUS BIOS update
file extension adups	Google Android data
file extension krm	Kenwood firmware data
file extension location	Microsoft Windows 10 registry data
file extension ovl	Overlay file
file extension sfc	Microsoft Windows system file check data
file extension nib	Interface Builder user interface resources
file extension mum	Microsoft Windows Update Package
file extension mof	Systems Management Server managed object format
file extension nxp	AdaOS profiling information for one execution file
file extension uxz	IBM Flex CMM update data
file extension sif	Microsoft Windows NT setup installation data
file extension pbd	PowerBuilder dynamic link library
file extension 211	ASUS BIOS update file
file extension aix	IBM AIX data
file extension spl	Microsoft Windows printing spool
file extension strings	Apple Mac strings
file extension swp	Swap file
file extension pid	Unix process ID
file extension mdmp	Microsoft Windows minidump
file extension grp	Microsoft Windows program group
file extension cpl	Microsoft Windows Control Panel data
file extension dev	Windows device driver
file extension sc	Framework II display driver
file extension gpd	Microsoft Windows universal printer unidrv minidriver
file extension appledouble	Apple AppleDouble resource data
file extension ovi	PC-9801 FM system data
file extension ecd	CoCut Plotter printer driver
file extension wdf	Microsoft Windows Driver Foundation data
file extension h86	CP/M data
file extension bif	Boot information file
file extension tlb	OLE type library
file extension bio	OS/2 BIOS file
file extension service	macOS (OS X) service application data
file extension mot	Linux load instructions
file extension identifier	Microsoft Windows zone identifier data
file extension qdz	Stratix V device driver
file extension bom	Apple Mac OS X Bill of Materials
file extension cdd	Chromeleon device driver
file extension acct	IBM AIX system data
file extension msc	Microsoft management console control data
file extension localized	macOS (OS X) system localization
file extension ko	Linux kernel module
file extension im4p	Apple iOS IMG4 payload data
file extension alx	BlackBerry application loader
file extension dt	Macintosh file data fork
file extension lan	Novell NetWare LAN driver
file extension osp	Crystal Semiconductor driver data
file extension vxd	Microsoft Windows virtual device driver
file extension nls	Microsoft National Language Support data
file extension wss	Microsoft Windows Sound System
file extension mpkg	Meta package
file extension h1c	Windows Vista file related to Assistance Platform (AP) help
file extension 100	Award BIOS Upgrade File version 1.0
file extension ami	AMI BIOS firmware data
file extension crmlog	Microsoft Windows CRM log
file extension shd	Microsoft Windows shadow spooler file
file extension rx	MS-DOS 7 data
file extension rel	Nintendo Wii relocatable module
file extension dio	iPaq 914c flash data
file extension ar	Linux/Unix command library
file extension hlp	Help file
file extension gid	Microsoft Windows Help general index
file extension lgs	Microsoft Windows application log
file extension nxs	AdaOS support module
file extension cb	Microsoft clean boot data
file extension kbd	Keyboard script file layout
file extension hv	Microsoft Windows Mobile hive
file extension rsrc	MAC OS resource data
file extension access	Java access control data
file extension bcd	Microsoft Windows boot configuration
file extension lbr	Lotus 1-2-3 display driver data
file extension 3_dpo	Ralink RT3070 Linux driver
file extension ddp	OS/2 device driver profile
file extension ann	Microsoft Windows Help annotation
file extension bcs	Microsoft Windows 95 browse information
file extension pdr	Windows Port device driver data
file extension htt	Microsoft HyperText template
file extension mft	Microsoft Windows NTFS master file table
file extension osc	Remote Installation Services client installation wizard
file extension hiv	Windows NT registry hive
file extension bnr	Nintento Wii homebrew data
file extension vdx	Windows 32-bit system driver
file extension gr2	Microsoft Windows screen driver
file extension folder	Microsoft Windows Explorer folder data
file extension pci	PCI miniport data
file extension savedsearch	Spotlight saved search
file extension vmlt	VMLF related data
file extension aug	Red Hat Linux shellvars file
file extension ext4	Fourth extended filesystem
file extension rwm	Windows Imaging Resource only image
file extension psf	Windows Server Update Services patch storage file
file extension mq	Microsoft Windows message data
file extension jfs	Linux/Unix Journaling file system
file extension tmc	Windows trace message control data
file extension log1	Microsoft Windows registry hive log
file extension vtd	Microsoft Windows custom virtual device driver
file extension component	macOS system component
file extension gzp	Gazelle system page
file extension evt	Microsoft Windows 2000 and XP event log
file extension h1t	Microsoft Windows Assistance Platform client help related data
file extension mci	Media Control Interface command script
file extension bbfw	iTunes firmware update
file extension xmo	Adobe Authorware movie driver
file extension vgd	VGA CADD display driver
file extension eas	OS/2 extended file attributes
file extension dbl	Microsoft Windows XP product activation data
file extension fseventsd	macOS (OS X) data
file extension tci	MityDSP-L138 / MityDSP-6748 memory modules cache
file extension mnu	MS-DOS mouse menu
file extension nkey	Silicon Graphics Onyx4 data
file extension fid	Microsoft Windows index
file extension cub	Windows Installer validation module
file extension cdm	Novell NetWare disk drivers NPA
file extension vrs	Corel WordPerfect video resource device driver
file extension jnilib	Java JNI library
file extension oem	OEM install data
file extension bash_history	Bash history data
file extension documentrevisions-v100	macOS (OS X) data
file extension hx1	Microsoft Windows data
file extension rfw	Rockchip firmware
file extension dwc	Emulex DWC firmware update file format
file extension mapimail	Windows Send To Mail Recipient data
file extension h1k	Keyword index - Microsoft Windows Assistance Platform client help related data
file extension wrs	Corel WordPerfect windows printer driver
file extension mydocs	Send to My Documents
file extension nos	JNOS system data
file extension lls	Windows system file
file extension inp	Sony HD camera system
file extension fx	Microsoft Windows prefetch data
file extension p5x	Microsoft Windows system data
file extension dll_1029	Microsoft Windows Dynamic Link Library
file extension ia64	HP-UX data
file extension low	PDP-10 low segment of a two-segment program
file extension journal_info_block	Apple Mac filesystem
file extension pxe	Linux, Unix network bootable image
file extension uce	Microsoft Windows XP system32 data
file extension grl	Microsoft Windows Update status data
file extension tbs	TuneUp style boot screen
file extension vga	Bitmap image
file extension file	AS/400 physical data
file extension msn	Microsoft Windows network related data
file extension mlb	Microsoft Windows Mobile media library
file extension kdmp	Microsoft Windows crash dump data
file extension pr2	dBase IV printer driver
file extension shsh	iOS ECID SHSH data
file extension grb	MS-DOS Shell Monitor data
file extension esn	Microsoft Windows XP System32 cache
file extension htw	Microsoft Windows data
file extension failurerequests	macOS (OS X) data
file extension install_backup	AVG shell extension module
file extension uaq	Microsoft Windows action queue file
file extension scap	Scap Mac OS X data
file extension srec	Motorola S-Records data
file extension qtz	Mac Quartz graphics
file extension hhc	HTML Help table of contents
file extension iot	Hitachi Ladder Editor IO comment
file extension ext2	Linux second extended file system
file extension dat_tureg_old	Windows Registry data
file extension vcn	NCDrive Vacon NX system software data
file extension xnc	Modbus Slave XNC driver application
file extension ina	MS-DOS data
file extension aql	AOL DLL library
file extension fwl	FileWrangler EXE library
file extension sucatalog	OS X (macOS) software update SUCatalog
file extension lproj	Mac localized project folder
file extension hdmp	Microsoft Windows heap dump data
file extension rm7	Casio registration memory data
file extension tha	Microsoft Windows Shell Common DLL file
file extension seed	Linux preseed data
file extension wdr	Psion Series 3 printer driver
file extension ara	ATI Radeon video driver
file extension ffw	Festo Firmware file
file extension system	macOS (OS X) system data
file extension pd0	SonTek firmware
file extension log2	Microsoft Windows registry hive log 2
file extension bash_profile	Bash interactive login shell
file extension bada	Samsung bada data
file extension spkg	Microsoft Windows Phone driver package
file extension idx_dll	Microsoft Office IDX_DLL file
file extension apple_partition_map	Apple partition scheme
file extension oth	Microsoft PowerToys Explorer tool data
file extension pmr	Microsoft Windows Performance Monitor report
file extension supported	MAC OS X file
file extension sdb	Windows Compatibility Solution Database
file extension lzt	HP StoreEver 1/8 G2 firmware data
file extension jlb	PAC Mate BX keyboard driver
file extension qky	Linux Quirky kernel data
file extension ubl	DM35x user boot loader data
file extension mui	Amiga MUI default class/library data
file extension qds	Microsoft Windows Server saved DsQuery data
file extension vet	VET antivirus system file
file extension cgk	BlueSoleil data
file extension prd	Microsoft Word for DOS printer driver
file extension 286	Microsoft Windows virtual device driver
file extension ln	UNIX lint data
file extension hcd	Huawei system data
file extension colorpicker	Apple Mac OS X color picker component
file extension kext	Apple Mac kernel extension
file extension rco	Sony PlayStation Portable PSP resource file
file extension hhk	Microsoft HTML help index
file extension zex	ZOOM MRS-802 system data
file extension hsancillary	Mac OS data
file extension trx_dll	Microsoft Office dynamic link library
file extension bsdiff	Cygwin data
file extension grm	Microsoft Windows data
file extension nld	AMD ATI Radeon video driver
file extension ltn	CD-ROM driver
file extension nvu	nVidia graphic driver data
file extension restorelist	Microsoft Windows file system permission
file extension $03	MS-DOS pipe
file extension inf	Autostart CDROM script
file extension _dl	Dynamic Link Library DLL file form
file extension qts	QuickTime system data
file extension cgz	Linux drivers archive
file extension sdb	Custom Application Compatibility Database
file extension devicemanifest-ms	Microsoft Windows device metadata
file extension cxn	Conexant driver
file extension bridgesupport	bridgesupport Mac OS X file extension
file extension rbh	RBH Access Technologies firmware
file extension 1092	Microsoft Windows data
file extension ham	Novell NetWare disk drivers NPA
file extension o00	Always Technology SCSI Controller Driver
file extension fs	Mac OS X file system plug-in
file extension rgu	Microsoft Windows Mobile registry entry
file extension rs	Windows Rating System rating data
file extension profile	Bash shell profile
file extension 4fs	Puppy Linux saved state
file extension n90	Apple iOS kernel cache
file extension ~bt	Microsoft Windows update directory
file extension aqm	CP/M information data
file extension pol	Microsoft Windows policy data
file extension 3gr	Windows Screen Grabber for MS-DOS applications VGA graphics driver
file extension qpr	OS/2 print queue device driver
file extension 2gr	Windows VGA graphic drivers
file extension cq	SYSGEN replacement data
file extension prt	Microsoft Windows directory
file extension 8xu	Texas Instruments TI-83 Plus operating system data
file extension doh	Geoworks GEOS dependency information
file extension hxi	Microsoft Help compiled storage file
file extension h1f	Microsoft Windows Assistance Platform client help data
file extension fstab	File system table
file extension cnv	Microsoft Word text conversion data
file extension file	macOS (OS X) data
file extension wpx	Adobe printer description
file extension emm	Expanded memory manager data
file extension os2	OS/2 system data
file extension searchindexcache	Apple Mac OS X (macOS) index cache
file extension 32s	Win32s data
file extension wdgt	Apple Mac OS X Dashboard widget
file extension qfilter	Mac ColorSync filter data
file extension equiv	IBM AIX host file
file extension ls_	Unix ls directory
file extension tnr	GPS Pathfinder ProXR/XRS firmware
file extension ov4	Overlay data
file extension monitorpanel	Apple Mac display panel plug-in file type
file extension lgx	Microsoft Windows received message data
file extension rsq	IBM 4690 Operating System data
file extension ov1	Overlay file
file extension bootefisignature	Mac system data
file extension msdm	Microsoft Windows system data
file extension gr3	Graphics device driver
file extension fgdump-log	Microsoft Windows fgdump data
file extension lgp	Microsoft Windows application log
file extension crp	MSI SecureDoc encrypted data
file extension dbfseventsd	Mac OS X data
file extension mdimporter	Spotlight importer setting file
file extension mpa	Palm memo
file extension nib	Adobe AIR data
file extension h1v	Microsoft Windows Assistance Platform task metadata
file extension installhelper	Apple Mac Install Helper document
file extension nxd	AdaOS debugging information for a module
file extension scr	MS-DOS DEBUG input
file extension sty	DirectMusic style data
file extension udf	Windows NT/XP uniqueness database
file extension vfs	Virtual file system index
file extension efires	Extensible Firmware Interface image
file extension migtable	Microsoft Windows data
file extension adm	Administrator policy template
file extension iswp	Apple iTunes iOS firmware update
file extension 3~6	Microsoft Windows 3.x system data
file extension grd	Drivers for GRX
file extension int	Sony HD camera system data
file extension sf0	Microsoft Windows sytem file check data
file extension sgn	Slax boot file
file extension mkext	Mac Mach kernel extension memory cache
file extension 001	Unix system file
file extension _vti_bin	SharePoint data
file extension sfe	Logomatic v2 system data
file extension cdev	Macintosh II control panel data
file extension xdsl	D-link router UK firmware update
file extension nu4	Norton Utilities DLL root data
file extension bud	Microsoft Windows binary printer description
file extension xms	Microsoft eXtended Memory specification data
file extension 000	CHKDSK found folder
file extension m$s	MindStor firmware update
file extension 0	PSERVER printer queue information data
file extension $$$	OS/2 operating system file type
file extension lex	Lex or Flex data
file extension ins	Microsoft Windows Internet Naming Service
file extension afs	FreeBSD data
file extension n81	Apple iOS kernel cache
file extension osax	AppleScript scripting addition data
file extension prs	Norton Viewer DLL library
file extension cpy	Atari Ramdrive CPY commands
file extension vid	MS-DOS video driver
file extension n90ap	iPhone Jailbreak firmware
file extension rat	Microsoft Windows rating system data
file extension 500	Linux data
file extension b	LILO Boot Loader image
file extension sparc	SunOS 4 data
file extension saver	Mac OS X Screen Saver
file extension pcm	LaserJet Printer Cartridge Metric for printer driver
file extension woa	Windows 3.x swap file
file extension ds	Desktop Korn Shell data
file extension ox2	Orangutan X2 firmware update
file extension sc	Unix spreadsheet commands
file extension acv	OS/2 audio driver
file extension fll	Visual FoxPro dynamic link library
file extension prefpane	Mac OS X System Preference Pane app
file extension 3fs	Puppy Linux saved state
file extension sl	HP-UX shared library
file extension 120	Award BIOS upgrade file
file extension cpi	Microsoft MS-DOS code page information
file extension ion	4DOS description
file extension dvd	MS-DOS hardware device driver
file extension vxx	IOsubsys drive data
file extension pid	Creative Labs driver
file extension ecw	System dll library
file extension mva	Matrox video card driver
file extension dpb	Microsoft Windows driver related data
file extension xxt	Dynamic Link Library
file extension icd	Microsoft Windows OpenGL installable client driver
file extension riscos	Acorn RISC OS data
file extension dan	AMD ATI Radeon video driver
file extension qlgenerator	Apple Quick Look plug-in
file extension prf	Microsoft Profiler output
file extension mcp	Amiga MUI preference class or library
file extension sid	Systems Management Server software inventory
file extension str	Screensaver
file extension aad	FreeBSD package
file extension mod	Microsoft Windows kernel module
file extension mojito	Limewire Kademlia data
file extension w20	Windows 2000 system data
file extension dis	Soundweb firmware update
file extension dl	Masked Dynamic Link Library
file extension macs	Apple Mac OS system data
file extension dmd	OS/2 Warp device manager driver
file extension osinstallmessages	macOS system data
file extension muimanifest	Microsoft Windows multilingual user interface data
file extension mps_	MPW Shell data
file extension mod	MS-DOS implementing support for Windows DLL's
file extension sdr	QuickView Pro for DOS soundcard driver
file extension dlm	Dynamic Link module
file extension spreporter	Mac OS X System Profiler Reporter file
file extension ifs	IBM OS/2 installable file system data
file extension 1pa	Microsoft Windows data
file extension cmg	cramfs ROM file system package
file extension b~k	Microsoft Windows 3.x data
file extension fx	DirectX D3DXEffect object
file extension tsk	Microsoft Windows system32 data
file extension do7	MS-DOS 7 data
file extension kmd	Clicker module output
file extension ftg	Microsoft Windows Help data
file extension ov2	Overlay file
file extension k48	Apple iOS kernel cache
file extension ctfsys	OS X Mach Kernel system data
file extension ndrv	Apple Mac OS system driver
file extension $b5	ProDOS 16 or GS/OS shell application
file extension hpfs	OS/2 High Performance File System
file extension scsi	Apple HDD setup data
file extension ov3	Overlay file
file extension ov5	Overlay file
file extension components	macOS system data
file extension 2sf	Puppy Linux data
file extension dir	Directory indicator
file extension hlx	ATI Radeon video driver
file extension exopc	ExoPC application data
file extension apd	IBM Lotus printer driver
file extension dvc	LoseThos partition drive file
file extension nst	Nokia Star Torrent system data
file extension kss	KDE screen saver
file extension shlb	MacOS system data
file extension dsr	Corel WordPerfect driver data
file extension nu6	Norton Utility system dll library
file extension pdl	Symbian OS printer driver
file extension aa	Unix data
file extension atahd	Puppy Linux ATA hard drive flag
file extension dsk	Novell NetWare disk driver
file extension add	Adapter device driver file
file extension upd	HP universal print driver
file extension not_terminated	Mac OS X audit log
file extension asd	Lotus screen driver
file extension scd	Systems Management Server (SMS) site control file deletion
file extension sf	OS/2 work place shell attribute storage
file extension group	Linux system data
file extension cachedump	Microsoft Windows system data
file extension rdz	Mandrake Linux install file
file extension rdl	Symbian recogniser library
file extension flg	Puppy Linux partition flag
file extension env	HP-95 environment data
file extension que	PDP-10 queue data
file extension aslquery	Apple MAC OS X console query
file extension dsp	Dr.Halo graphics display driver
file extension mob	PEN Windows device definition file
file extension wcx	Microsoft Windows workspace configuration
file extension vap	NetWare 2 value added process file
file extension qcc	Niobrata QUCM firmware
file extension cin	OS/2 change control file
file extension fs	NetBSD system data
file extension bsd	FacetWin bitwise backup set file
file extension hpc	System dynamic library file
file extension chs	Microsoft Windows Chinese noise-word list
file extension aws	ActiveWords System file
file extension ali	BeOS ALI ata
file extension plt	EPOC software platform data
file extension adv	Gravis Ultrasound virtual device driver file
file extension dif	OS/2 display information file
file extension rtb	NAT proxy servers file
file extension plk	AMD ATI Radeon video driver
file extension quicktimecomponents	Mac OS X system file
file extension ioplist	Apple Mac OS X ioplist file
file extension fin	AMD ATI Radeon video driver
file extension cht	Microsoft Windows Chinese noise-word list file
file extension rpp	Symbian OS pre-processed resource
file extension cnm	Microsoft Windows application menu options and setup file
file extension le	le Mac OS X file
file extension flt	OS/2 warp filter device driver file
file extension nlm	Novell Netware loadable module 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
file extension icap	Internet preference file
file extension ril	Google Android radio interface library
file extension ad	UNIX application default resource file

System file extensions

Browse file extensions by file type category:

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.

Browse by extension type: