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 dll | Dynamic Link Library |
file extension dat | Program data |
file extension ds_store | macOS folder information |
file extension sys | System file |
file extension etl | Microsoft Windows trace log |
file extension h1s | Microsoft Windows Assistance Platform client help document |
file extension shs | Microsoft Windows 95/98 clipboard data |
file extension so | ELF shared library |
file extension scr | MS Windows screensaver |
file extension efi | Extensible Firmware Interface |
file extension sfcache | ReadyBoost cache |
file extension rom | Read Only Memory image |
file extension 0 | Linux shared library link |
file extension mui | MultiLanguage Windows resource data |
file extension pat | Synology DiskStation DSM update |
file extension rio | IBM AIX system data |
file extension pf | Microsoft Windows prefetch data |
file extension dump | Dump data |
file extension idx | Index file |
file extension bzi | Darik's Boot And Nuke kernel data file |
file extension ocx | ActiveX Control |
file extension cat | Microsoft Security Catalog |
file extension pcf | Microsoft Source Profiler profiler command |
file extension reg | Windows registry data |
file extension evtx | Microsoft Windows event log |
file extension inf | Windows installation script |
file extension regtrans-ms | Microsoft Windows registry changes temporary data |
file extension gadget | Windows sidebar gadget |
file extension sha | Unix SHAR archive |
file extension key | Microsoft Windows 7 registry key file |
file extension man | Microsoft Windows 2000/XP mandatory user profile |
file extension drv | Microsoft Windows device driver |
file extension lock | Lock data |
file extension blf | Microsoft Windows registry data file |
file extension sfs | Squashfs file archive |
file extension _ipod_control | iPod control data file |
file extension payload | Microsoft Windows Mobile data |
file extension apdisk | Apple macOS disk information data |
file extension job | Microsoft Windows Task Scheduler task object |
file extension rtp | Software update |
file extension scc | Visual SourceSafe control data |
file extension ddz | Adaptec SCO Unix driver image |
file extension scexe | HP iL02 firmware update |
file extension x86 | Microsoft Office dynamic link library |
file extension dev | Windows device driver |
file extension mdmp | Microsoft Windows minidump |
file extension spl | Microsoft Windows printing spool |
file extension marker | Microsoft Windows 10 system data |
file extension cdfs | Compact Disc File System |
file extension pbd | PowerBuilder dynamic link library |
file extension aix | IBM AIX data |
file extension nib | Interface Builder user interface resources |
file extension mof | Systems Management Server managed object format |
file extension swp | Swap file |
file extension ovl | Overlay file |
file extension 212 | ASUS BIOS update |
file extension 211 | ASUS BIOS update file |
file extension grp | Microsoft Windows program group |
file extension sif | Microsoft Windows NT setup installation data |
file extension location | Microsoft Windows 10 registry data |
file extension mum | Microsoft Windows Update Package |
file extension mpkg | Meta package |
file extension appledouble | Apple AppleDouble resource data |
file extension cpl | Microsoft Windows Control Panel data |
file extension krm | Kenwood firmware data |
file extension acct | IBM AIX system data |
file extension adups | Google Android data |
file extension strings | Apple Mac strings |
file extension pid | Unix process ID |
file extension sfc | Microsoft Windows system file check data |
file extension nxp | AdaOS profiling information for one execution file |
file extension tlb | OLE type library |
file extension sc | Framework II display driver |
file extension gpd | Microsoft Windows universal printer unidrv minidriver |
file extension vxd | Microsoft Windows virtual device driver |
file extension uxz | IBM Flex CMM update data |
file extension ecd | CoCut Plotter printer driver |
file extension bio | OS/2 BIOS file |
file extension wdf | Microsoft Windows Driver Foundation data |
file extension msc | Microsoft management console control data |
file extension cdd | Chromeleon device driver |
file extension bif | Boot information file |
file extension ovi | PC-9801 FM system data |
file extension qdz | Stratix V device driver |
file extension ext4 | Fourth extended filesystem |
file extension mot | Linux load instructions |
file extension bom | Apple Mac OS X Bill of Materials |
file extension h86 | CP/M data |
file extension dt | Macintosh file data fork |
file extension im4p | Apple iOS IMG4 payload data |
file extension identifier | Microsoft Windows zone identifier data |
file extension service | macOS (OS X) service application data |
file extension alx | BlackBerry application loader |
file extension ko | Linux kernel module |
file extension wss | Microsoft Windows Sound System |
file extension lan | Novell NetWare LAN driver |
file extension nls | Microsoft National Language Support data |
file extension bcd | Microsoft Windows boot configuration |
file extension localized | macOS (OS X) system localization |
file extension 100 | Award BIOS Upgrade File version 1.0 |
file extension crmlog | Microsoft Windows CRM log |
file extension h1c | Windows Vista file related to Assistance Platform (AP) help |
file extension lgs | Microsoft Windows application log |
file extension rel | Nintendo Wii relocatable module |
file extension osp | Crystal Semiconductor driver data |
file extension hlp | Help file |
file extension cb | Microsoft clean boot data |
file extension shd | Microsoft Windows shadow spooler file |
file extension mft | Microsoft Windows NTFS master file table |
file extension ami | AMI BIOS firmware data |
file extension kbd | Keyboard script file layout |
file extension ar | Linux/Unix command library |
file extension hiv | Windows NT registry hive |
file extension psf | Windows Server Update Services patch storage file |
file extension rsrc | MAC OS resource data |
file extension dio | iPaq 914c flash data |
file extension gid | Microsoft Windows Help general index |
file extension hv | Microsoft Windows Mobile hive |
file extension rx | MS-DOS 7 data |
file extension nxs | AdaOS support module |
file extension bnr | Nintento Wii homebrew data |
file extension folder | Microsoft Windows Explorer folder data |
file extension lbr | Lotus 1-2-3 display driver data |
file extension access | Java access control data |
file extension osc | Remote Installation Services client installation wizard |
file extension ddp | OS/2 device driver profile |
file extension vdx | Windows 32-bit system driver |
file extension ann | Microsoft Windows Help annotation |
file extension mq | Microsoft Windows message data |
file extension fseventsd | macOS (OS X) data |
file extension 3_dpo | Ralink RT3070 Linux driver |
file extension evt | Microsoft Windows 2000 and XP event log |
file extension bcs | Microsoft Windows 95 browse information |
file extension gr2 | Microsoft Windows screen driver |
file extension htt | Microsoft HyperText template |
file extension tmc | Windows trace message control data |
file extension vgd | VGA CADD display driver |
file extension pci | PCI miniport data |
file extension pdr | Windows Port device driver data |
file extension component | macOS system component |
file extension h1t | Microsoft Windows Assistance Platform client help related data |
file extension aug | Red Hat Linux shellvars file |
file extension fid | Microsoft Windows index |
file extension log1 | Microsoft Windows registry hive log |
file extension bash_history | Bash history data |
file extension savedsearch | Spotlight saved search |
file extension inp | Sony HD camera system |
file extension vcn | NCDrive Vacon NX system software data |
file extension cub | Windows Installer validation module |
file extension h1k | Keyword index - Microsoft Windows Assistance Platform client help related data |
file extension jfs | Linux/Unix Journaling file system |
file extension rwm | Windows Imaging Resource only image |
file extension gzp | Gazelle system page |
file extension seed | Linux preseed data |
file extension vmlt | VMLF related data |
file extension cdm | Novell NetWare disk drivers NPA |
file extension mci | Media Control Interface command script |
file extension dbl | Microsoft Windows XP product activation data |
file extension documentrevisions-v100 | macOS (OS X) data |
file extension vtd | Microsoft Windows custom virtual device driver |
file extension bbfw | iTunes firmware update |
file extension eas | OS/2 extended file attributes |
file extension mnu | MS-DOS mouse menu |
file extension oem | OEM install data |
file extension jnilib | Java JNI library |
file extension rfw | Rockchip firmware |
file extension mlb | Microsoft Windows Mobile media library |
file extension log2 | Microsoft Windows registry hive log 2 |
file extension mapimail | Windows Send To Mail Recipient data |
file extension xmo | Adobe Authorware movie driver |
file extension fx | Microsoft Windows prefetch data |
file extension tci | MityDSP-L138 / MityDSP-6748 memory modules cache |
file extension wrs | Corel WordPerfect windows printer driver |
file extension nkey | Silicon Graphics Onyx4 data |
file extension system | macOS (OS X) system data |
file extension nos | JNOS system data |
file extension shsh | iOS ECID SHSH data |
file extension vga | Bitmap image |
file extension hx1 | Microsoft Windows data |
file extension fwl | FileWrangler EXE library |
file extension vrs | Corel WordPerfect video resource device driver |
file extension p5x | Microsoft Windows system data |
file extension lls | Windows system file |
file extension tbs | TuneUp style boot screen |
file extension mui | Amiga MUI default class/library data |
file extension file | AS/400 physical data |
file extension dwc | Emulex DWC firmware update file format |
file extension esn | Microsoft Windows XP System32 cache |
file extension kdmp | Microsoft Windows crash dump data |
file extension pxe | Linux, Unix network bootable image |
file extension msn | Microsoft Windows network related data |
file extension qtz | Mac Quartz graphics |
file extension grl | Microsoft Windows Update status data |
file extension ins | Microsoft Windows Internet Naming Service |
file extension iot | Hitachi Ladder Editor IO comment |
file extension uce | Microsoft Windows XP system32 data |
file extension pr2 | dBase IV printer driver |
file extension grb | MS-DOS Shell Monitor data |
file extension ia64 | HP-UX data |
file extension dll_1029 | Microsoft Windows Dynamic Link Library |
file extension hhc | HTML Help table of contents |
file extension mydocs | Send to My Documents |
file extension low | PDP-10 low segment of a two-segment program |
file extension ara | ATI Radeon video driver |
file extension scap | Scap Mac OS X data |
file extension ext2 | Linux second extended file system |
file extension journal_info_block | Apple Mac filesystem |
file extension install_backup | AVG shell extension module |
file extension srec | Motorola S-Records data |
file extension lproj | Mac localized project folder |
file extension bash_profile | Bash interactive login shell |
file extension failurerequests | macOS (OS X) data |
file extension htw | Microsoft Windows data |
file extension kext | Apple Mac kernel extension |
file extension uaq | Microsoft Windows action queue file |
file extension ina | MS-DOS data |
file extension sucatalog | OS X (macOS) software update SUCatalog |
file extension xnc | Modbus Slave XNC driver application |
file extension colorpicker | Apple Mac OS X color picker component |
file extension aql | AOL DLL library |
file extension pd0 | SonTek firmware |
file extension wdr | Psion Series 3 printer driver |
file extension jlb | PAC Mate BX keyboard driver |
file extension dat_tureg_old | Windows Registry data |
file extension hdmp | Microsoft Windows heap dump data |
file extension pmr | Microsoft Windows Performance Monitor report |
file extension sdb | Windows Compatibility Solution Database |
file extension spkg | Microsoft Windows Phone driver package |
file extension rm7 | Casio registration memory data |
file extension bada | Samsung bada data |
file extension lzt | HP StoreEver 1/8 G2 firmware data |
file extension oth | Microsoft PowerToys Explorer tool data |
file extension supported | MAC OS X file |
file extension tha | Microsoft Windows Shell Common DLL file |
file extension hhk | Microsoft HTML help index |
file extension prd | Microsoft Word for DOS printer driver |
file extension apple_partition_map | Apple partition scheme |
file extension ffw | Festo Firmware file |
file extension fs | Mac OS X file system plug-in |
file extension qky | Linux Quirky kernel data |
file extension hcd | Huawei system data |
file extension ubl | DM35x user boot loader data |
file extension vet | VET antivirus system file |
file extension file | macOS (OS X) data |
file extension zex | ZOOM MRS-802 system data |
file extension idx_dll | Microsoft Office IDX_DLL file |
file extension qds | Microsoft Windows Server saved DsQuery data |
file extension ln | UNIX lint data |
file extension cgk | BlueSoleil data |
file extension cnv | Microsoft Word text conversion data |
file extension 286 | Microsoft Windows virtual device driver |
file extension _dl | Dynamic Link Library DLL file form |
file extension $03 | MS-DOS pipe |
file extension grm | Microsoft Windows data |
file extension bridgesupport | bridgesupport Mac OS X file extension |
file extension nvu | nVidia graphic driver data |
file extension trx_dll | Microsoft Office dynamic link library |
file extension devicemanifest-ms | Microsoft Windows device metadata |
file extension pol | Microsoft Windows policy data |
file extension bsdiff | Cygwin data |
file extension inf | Autostart CDROM script |
file extension hsancillary | Mac OS data |
file extension aqm | CP/M information data |
file extension sdb | Custom Application Compatibility Database |
file extension crp | MSI SecureDoc encrypted data |
file extension cgz | Linux drivers archive |
file extension cxn | Conexant driver |
file extension rco | Sony PlayStation Portable PSP resource file |
file extension ltn | CD-ROM driver |
file extension qts | QuickTime system data |
file extension nld | AMD ATI Radeon video driver |
file extension rbh | RBH Access Technologies firmware |
file extension ham | Novell NetWare disk drivers NPA |
file extension qpr | OS/2 print queue device driver |
file extension prt | Microsoft Windows directory |
file extension 1092 | Microsoft Windows data |
file extension profile | Bash shell profile |
file extension restorelist | Microsoft Windows file system permission |
file extension cq | SYSGEN replacement data |
file extension 4fs | Puppy Linux saved state |
file extension hxi | Microsoft Help compiled storage file |
file extension rgu | Microsoft Windows Mobile registry entry |
file extension o00 | Always Technology SCSI Controller Driver |
file extension 3gr | Windows Screen Grabber for MS-DOS applications VGA graphics driver |
file extension fstab | File system table |
file extension n90 | Apple iOS kernel cache |
file extension wdgt | Apple Mac OS X Dashboard widget |
file extension doh | Geoworks GEOS dependency information |
file extension rs | Windows Rating System rating data |
file extension wpx | Adobe printer description |
file extension h1f | Microsoft Windows Assistance Platform client help data |
file extension mpa | Palm memo |
file extension ~bt | Microsoft Windows update directory |
file extension os2 | OS/2 system data |
file extension rsq | IBM 4690 Operating System​ data |
file extension searchindexcache | Apple Mac OS X (macOS) index cache |
file extension 8xu | Texas Instruments TI-83 Plus operating system data |
file extension 2gr | Windows VGA graphic drivers |
file extension lgp | Microsoft Windows application log |
file extension equiv | IBM AIX host file |
file extension tnr | GPS Pathfinder ProXR/XRS firmware |
file extension ls_ | Unix ls directory |
file extension lgx | Microsoft Windows received message data |
file extension emm | Expanded memory manager data |
file extension 32s | Win32s data |
file extension prs | Norton Viewer DLL library |
file extension scr | MS-DOS DEBUG input |
file extension qfilter | Mac ColorSync filter data |
file extension monitorpanel | Apple Mac display panel plug-in file type |
file extension int | Sony HD camera system data |
file extension ov1 | Overlay file |
file extension ov4 | Overlay data |
file extension mdimporter | Spotlight importer setting file |
file extension bootefisignature | Mac system data |
file extension dbfseventsd | Mac OS X data |
file extension msdm | Microsoft Windows system data |
file extension adm | Administrator policy template |
file extension udf | Windows NT/XP uniqueness database |
file extension gr3 | Graphics device driver |
file extension h1v | Microsoft Windows Assistance Platform task metadata |
file extension 001 | Unix system file |
file extension fgdump-log | Microsoft Windows fgdump data |
file extension sty | DirectMusic style data |
file extension nib | Adobe AIR data |
file extension installhelper | Apple Mac Install Helper document |
file extension efires | Extensible Firmware Interface image |
file extension grd | Drivers for GRX |
file extension _vti_bin | SharePoint data |
file extension sgn | Slax boot file |
file extension iswp | Apple iTunes iOS firmware update |
file extension nxd | AdaOS debugging information for a module |
file extension migtable | Microsoft Windows data |
file extension pcm | LaserJet Printer Cartridge Metric for printer driver |
file extension $$$ | OS/2 operating system file type |
file extension saver | Mac OS X Screen Saver |
file extension xdsl | D-link router UK firmware update |
file extension lex | Lex or Flex data |
file extension mkext | Mac Mach kernel extension memory cache |
file extension 000 | CHKDSK found folder |
file extension vfs | Virtual file system index |
file extension 3~6 | Microsoft Windows 3.x system data |
file extension vid | MS-DOS video driver |
file extension bud | Microsoft Windows binary printer description |
file extension osax | AppleScript scripting addition data |
file extension cdev | Macintosh II control panel data |
file extension sf0 | Microsoft Windows sytem file check data |
file extension sfe | Logomatic v2 system data |
file extension afs | FreeBSD data |
file extension ox2 | Orangutan X2 firmware update |
file extension sparc | SunOS 4 data |
file extension m$s | MindStor firmware update |
file extension cpy | Atari Ramdrive CPY commands |
file extension rat | Microsoft Windows rating system data |
file extension cpi | Microsoft MS-DOS code page information |
file extension n90ap | iPhone Jailbreak firmware |
file extension riscos | Acorn RISC OS data |
file extension ecw | System dll library |
file extension 500 | Linux data |
file extension xms | Microsoft eXtended Memory specification data |
file extension n81 | Apple iOS kernel cache |
file extension nu4 | Norton Utilities DLL root data |
file extension 0 | PSERVER printer queue information data |
file extension sl | HP-UX shared library |
file extension prefpane | Mac OS X System Preference Pane app |
file extension b | LILO Boot Loader image |
file extension 120 | Award BIOS upgrade file |
file extension woa | Windows 3.x swap file |
file extension sdr | QuickView Pro for DOS soundcard driver |
file extension ion | 4DOS description |
file extension dvd | MS-DOS hardware device driver |
file extension acv | OS/2 audio driver |
file extension fll | Visual FoxPro dynamic link library |
file extension str | Screensaver |
file extension 3fs | Puppy Linux saved state |
file extension w20 | Windows 2000 system data |
file extension vxx | IOsubsys drive data |
file extension ds | Desktop Korn Shell data |
file extension sid | Systems Management Server software inventory |
file extension dvc | LoseThos partition drive file |
file extension dpb | Microsoft Windows driver related data |
file extension qlgenerator | Apple Quick Look plug-in |
file extension pid | Creative Labs driver |
file extension dlm | Dynamic Link module |
file extension mva | Matrox video card driver |
file extension fx | DirectX D3DXEffect object |
file extension prf | Microsoft Profiler output |
file extension xxt | Dynamic Link Library |
file extension aad | FreeBSD package |
file extension icd | Microsoft Windows OpenGL installable client driver |
file extension mod | Microsoft Windows kernel module |
file extension mojito | Limewire Kademlia data |
file extension ov2 | Overlay file |
file extension dis | Soundweb firmware update |
file extension mod | MS-DOS implementing support for Windows DLL's |
file extension dir | Directory indicator |
file extension cmg | cramfs ROM file system package |
file extension do7 | MS-DOS 7 data |
file extension macs | Apple Mac OS system data |
file extension dl | Masked Dynamic Link Library |
file extension ndrv | Apple Mac OS system driver |
file extension mcp | Amiga MUI preference class or library |
file extension osinstallmessages | macOS system data |
file extension hpfs | OS/2 High Performance File System |
file extension ifs | IBM OS/2 installable file system data |
file extension tsk | Microsoft Windows system32 data |
file extension spreporter | Mac OS X System Profiler Reporter file |
file extension apd | IBM Lotus printer driver |
file extension k48 | Apple iOS kernel cache |
file extension scsi | Apple HDD setup data |
file extension ftg | Microsoft Windows Help data |
file extension ov3 | Overlay file |
file extension aslquery | Apple MAC OS X console query |
file extension asd | Lotus screen driver |
file extension atahd | Puppy Linux ATA hard drive flag |
file extension 1pa | Microsoft Windows data |
file extension b~k | Microsoft Windows 3.x data |
file extension muimanifest | Microsoft Windows multilingual user interface data |
file extension dan | AMD ATI Radeon video driver |
file extension hlx | ATI Radeon video driver |
file extension cin | OS/2 change control file |
file extension dmd | OS/2 Warp device manager driver |
file extension pdl | Symbian OS printer driver |
file extension group | Linux system data |
file extension ctfsys | OS X Mach Kernel system data |
file extension components | macOS system data |
file extension aa | Unix data |
file extension mps_ | MPW Shell data |
file extension rdl | Symbian recogniser library |
file extension add | Adapter device driver file |
file extension ov5 | Overlay file |
file extension scd | Systems Management Server (SMS) site control file deletion |
file extension kmd | Clicker module output |
file extension shlb | MacOS system data |
file extension $b5 | ProDOS 16 or GS/OS shell application |
file extension upd | HP universal print driver |
file extension 2sf | Puppy Linux data |
file extension ioplist | Apple Mac OS X ioplist file |
file extension dsr | Corel WordPerfect driver data |
file extension wcx | Microsoft Windows workspace configuration |
file extension cachedump | Microsoft Windows system data |
file extension nst | Nokia Star Torrent system data |
file extension kss | KDE screen saver |
file extension rdz | Mandrake Linux install file |
file extension rpp | Symbian OS pre-processed resource |
file extension dsk | Novell NetWare disk driver |
file extension exopc | ExoPC application data |
file extension cht | Microsoft Windows Chinese noise-word list file |
file extension plt | EPOC software platform data |
file extension rtb | NAT proxy servers file |
file extension que | PDP-10 queue data |
file extension nu6 | Norton Utility system dll library |
file extension vap | NetWare 2 value added process file |
file extension aws | ActiveWords System file |
file extension sf | OS/2 work place shell attribute storage |
file extension not_terminated | Mac OS X audit log |
file extension bsd | FacetWin bitwise backup set file |
file extension plk | AMD ATI Radeon video driver |
file extension env | HP-95 environment data |
file extension hpc | System dynamic library file |
file extension nlm | Novell Netware loadable module file |
file extension ali | BeOS ALI ata |
file extension chs | Microsoft Windows Chinese noise-word list |
file extension flg | Puppy Linux partition flag |
file extension fs | NetBSD system data |
file extension ril | Google Android radio interface library |
file extension cnm | Microsoft Windows application menu options and setup file |
file extension mob | PEN Windows device definition file |
file extension irix6 | Irix 6 file |
file extension flt | OS/2 warp filter device driver file |
file extension dsp | Dr.Halo graphics display driver |
file extension novs | Novell NetWare Control Center file |
file extension qcc | Niobrata QUCM firmware |
file extension irc | Nevo Infra-Red device code file format |
file extension dif | OS/2 display information file |
file extension adv | Gravis Ultrasound virtual device driver file |
file extension quicktimecomponents | Mac OS X system file |
file extension fin | AMD ATI Radeon video driver |
file extension le | le Mac OS X file |
file extension icap | Internet preference file |
file extension sdev | Apple System 7 Control Strip module |
file extension ad | UNIX application default resource file |