| .l | Lex Language Source Format |
| .l01 | ARC Digitized Raster Graphics Format |
| .l2l | IBM Voice Type Languages Addword |
| .l2p | BM Voice Type Languages Addword |
| .l2r | Lineage II Replay |
| .l32 | Swift Line 21 Caption |
| .l3d | Black & White Graphics Format |
| .l4d | Cinema 4D Layout Settings Format |
| .l5k | RSLogix 5000 |
| .l6t | Line 6 GearBox Tone Format |
| .la | La Lossless Compressed Audio Format |
| .la0 | LucasArts Game Data |
| .la1 | LucasArts Game Data |
| .la2 | LucasArts Game Data |
| .laa | LucasArts AdLib Audio |
| .lab | Corel WordPerfect Label Definition Format |
| .labx | CASSY Lab |
| .laby | Laby Level Format |
| .laccdb | Microsoft Access 2007/2010 Database Lock Format |
| .lad | Daylon Leveller Animation Data |
| .lae | Local Authentication Export |
| .laf | Lingoes Appendix |
| .lai | GNU Libtool Temporary |
| .lak | Kashmir |
| .lam | Netscape Media Player Streaming Audio Metafile |
| .lamp | ArchiCAD For MAC Geometric Description Language |
| .lan | Erdas LAN Image Format |
| .lanalyser | Novell Netware LANalyzer Trace |
| .land | Userland Frontier |
| .lang | Skype Language Settings Format |
| .lao | EPSON SMART PANEL |
| .lar | Liquid Audio Player Registration |
| .las | LIDAR Data Exchange Format |
| .lasso | Lasso Database Driven Web Page |
| .lastbuildstate | MSBuild Exported Build |
| .lastlogin | Minecraft User Settings Format |
| .lat | LaTeX |
| .latex | Latex Text Document Format |
| .launch | Zend Studio Debugger Configuration |
| .launcherex_sourcerecord | Foston Google Android |
| .lav | Liquid Audio Player Voucher |
| .lavs | Liquid Audio Secured Download |
| .lax | AnetHelpTool JavaHelp Viewer |
| .lay | Apple DVD Studio Pro Layout Format |
| .layerdiagram | Microsoft Visual Studio Layer Diagram |
| .layout | Apple MainStage Layout Format |
| .layoutdesigner | QuickBooks Layout Designer Template |
| .lb | LBwin Project |
| .lba | Liberty BASIC |
| .lbc | Cloaked Affiliate Link Builder Saved Link Format |
| .lbd | Life Balance User Data |
| .lbe | Life Balance Xml-based Data Exchange |
| .lbf | Bioshock 2 Configuration |
| .lbg | DBASE IV Label Generator Data |
| .lbi | Adobe Dreamweaver Library Format |
| .lbk | VersaPro Local Logic Block Backup |
| .lbl | Database Label Format Format |
| .lbm | Interleaved Bitmap Format |
| .lbo | DBASE IV Compiled Label |
| .lbp | ProWORX Nxt Logic Pointer |
| .lbr | EAGLE Library Format |
| .lbs | Omnis Studio Application Format |
| .lbt | Visual FoxPro Additional Label Description Format |
| .lbu | Cloaked Affiliate Link Builder Settings Format |
| .lbx | Visual FoxPro Main (DBF) Label Description Format |
| .lbxcol | Libronix DLS Resource Collection |
| .LBXDTP | Libronix DLS Data Type |
| .lbxlls | Logos Libronix 3.0 |
| .lbxoeb | Libronix DLS Resource |
| .lcb | Concept2 LogCard Utility LogCard Backup Image |
| .lcc | Capture One PRO Format |
| .lcd | Abbyy Finereader Sprint Format |
| .lcf | ArchiCAD Library Container Format |
| .lch | IBM Works For OS/2 Chart |
| .lci | IBM Voice Type Languages Newuser |
| .lck | Lock Format |
| .lcl | Localization |
| .lclw | ClarisWorks Art Library |
| .lcm | Lipikar Custom Map Format |
| .lcn | Corel WordPerfect Dictionary Format |
| .lcp | FARSITE Landscape Data |
| .lcs | ACT! History |
| .lct | Electrical Filter Design |
| .lcx | LC Model |
| .ld | Telix Long Distance Codes |
| .ld1 | DBASE Overlay |
| .ld2 | Lingoes Compiled Dictionary Format |
| .ld4 | ACCPAC Plus Menu |
| .lda | LaserData Image Format |
| .ldb | Microsoft Access Record-Locking Information Format |
| .ldd | LEGO Digital Designer |
| .ldf | Microsoft SQL Server Log Format |
| .ldi | LDIF Address Book Interchange Format |
| .ldif | LDIF Address Book Interchange Format |
| .ldl | Corel Paradox Delivered Library |
| .ldm | VolumeViz Multi-resolution Volume Format |
| .ldmt | Likno Drop-Down Menu Trees |
| .ldo | Nova Logic Game Loadout Text |
| .ldp | Label Designer Plus DELUXE Data |
| .ldr | LDraw Model Format |
| .lds | Linux Compile Time Header Format |
| .ldt | ZENAX Source EULUMDAT Format |
| .ldw | Virtual Villagers Save Game Format |
| .ldx | Liquid Studio Liquid Executable Bytecode |
| .ldz | Microsoft Visual Studio DSM Project |
| .le | Le Mac OS X |
| .led | Sony AIBO AIBO LED File Format |
| .lef | LEN Exchange Format |
| .leg | LEGOCAD |
| .legal | DaveTech Legal Document |
| .lei | Leica SP1 Image Session |
| .lemon | LemonShare.net Download Format |
| .lens | Autodesk Stitcher Camera Profile |
| .lep | Label And Envelope Designer Plus 2000 |
| .less | LESS Style Sheet Format |
| .let | Nuke Randomic Life Generator |
| .letter | Undeliverable Mail Format |
| .lev | Worms Map |
| .lex | Adobe Linguistic Library Data Format |
| .lf | SoftwareKey License |
| .lfa | Life Forms |
| .lfe | LFClient Document |
| .lff | LucasFilm Format Image Format |
| .lfm | LifeForm Format |
| .lfo | Camel Audio Alchemy Preset Format |
| .lfp | IPRO View Database Format |
| .lfs | Samsung Test Picture Image Format |
| .lft | ChiWriter Laser Printer Font |
| .lg0 | IBM Tivoli Monitoring Log |
| .lg1 | IBM Tivoli Monitoring Log Backup |
| .lg2 | HotMux Thermocouple Data Log |
| .lga | Microsoft Windows Application Log |
| .lgb | QuickBooks Little Green Box |
| .lgc | SimpleK Database Format |
| .lgd | Windows Application Log |
| .lgf | Microsoft Windows Application Log |
| .lgg | Microsoft Windows Application Log |
| .lgh | HMI Historical Log Format |
| .lgi | Multimedia Logic Format |
| .lgj | Microsoft Windows Application Log |
| .lgk | Microsoft Windows Application Log |
| .lgl | LeechGet Download Queue Format |
| .lgm | Microsoft Windows Application Log |
| .lgn | Microsoft Windows Application Log |
| .lgo | Logo Instructions Format |
| .lgp | Final Fantasy Game Archive Format |
| .lgq | Microsoft Windows Application Log |
| .lgr | Microsoft Windows Application Log |
| .lgs | Microsoft Windows Application Log |
| .lgt | Urban Chaos Game |
| .lgv | Debugging Tools For Windows Logger Log |
| .lgw | ANSYS |
| .lgz | Windows Application Log |
| .lha | LH ARC Compressed Archive |
| .lharc | LH ARC Compressed Archive |
| .lhr | Quicken Financial Life For Mac Financial Data Format |
| .lhs | Literate Haskell Programming Language Source Code Format |
| .lhw | LHWarp Compressed Amiga Archive |
| .lhx | LineTracker Firmware Upgrade |
| .lhz | LHA Compressed File Archive |
| .li3d | BeLight Live Interior 3D Design Format |
| .lia | P-CAD Schematics Library |
| .lib | Microsoft Linker Input Library Format |
| .lib4d | Cinema 4D Library |
| .library | CATIA Library |
| .library-ms | Microsoft Windows 7 Library Description Format |
| .lic | Unix Software License Format |
| .licensekey | Coriolis IPartition License Information Format |
| .licenses | Microsoft Visual Studio Licensed Classes Format |
| .lickey | AVS4YOU License Key |
| .licrypt | Encrypted |
| .licx | Microsoft Visual Studio License Format |
| .lid | Quicken 2002 Deluxe Format |
| .lif | Compressed Format Archive (CA-Clipper Installer) |
| .life | LIGHT Format |
| .lig | INet-Server |
| .lightwave | Lightwave 3D Layered Object |
| .lik | Trojan.Win32.Agent.lik |
| .lily | PCSX2 LilyPad Configuration Format |
| .lin | AutoCAD Linetype Definition |
| .link | Apple IPod Link Format |
| .linux | Linux |
| .linx | Bridge Base Format |
| .lip | SLIP Format Format |
| .liquid | Shopify Liquid Template |
| .lir | ADI Ocelot Settings |
| .lis | Structured Query Reporting Output Format |
| .lisp | LISP Translators Format |
| .list | JAR Index Format |
| .lit | Microsoft Reader EBook Format |
| .litemod | Minecraft Mod |
| .little | Mozilla Firefox Start-up Cache |
| .liv | Living Actor Actor |
| .livereg | Symantec Livereg Antivirus Session Format |
| .livesubscribe | Symantec Antivirus Update Catalog |
| .liveupdate | Symantec Liveupdate Format |
| .lix | ExtendSim Library Format |
| .lizd | BeLight Live Interior 3D Compressed Design Format |
| .ljp | Lossless JPEG Bitmap Image Format |
| .lk# | Autodesk Multi-user Coordination Lock |
| .lkg | HP-UX Configuration |
| .lkh | Worm.Generic.LKH Virus |
| .lko | Microsoft Outlook Express |
| .lkr | MPLAB Linker |
| .ll | List & Label Preview Format |
| .llb | LabVIEW Application Program Library Format |
| .llc | LapLink Saved Connection |
| .llm | Linden Lab Mesh Format |
| .llp | VersaPro Local Logic Block |
| .lls | Windows System |
| .llt | Liquidity Lighthouse Transaction Format |
| .llv | Lizard Safeguard License |
| .llx | LabVIEW Library Backup Format |
| .lm4 | Steinberg VST Sample |
| .lma | Learning Mobile Author (LMA) Project |
| .lmbs | Adobe Photoshop For Mac Filter |
| .lmd | Abbyy Finereader Sprint |
| .lmf | Library Mapping And Altera Data Interchange |
| .lmg | CryENGINE Locomotion Group Animation |
| .lmh | Memory Hacking Software Memory |
| .lmk | Sothink Logo Maker Logo Format |
| .lmlpack | Kashmir 3D Link |
| .lmp | Doom Recorded Demo |
| .lmr | QuickBooks Loan Manager Data |
| .lms | Light-O-Rama Musical Sequence Format |
| .lmt | RPG Maker 2000/2003 Map Tree |
| .lmu | RPG Maker Map Format |
| .lmv | Adobe Flash Source Code |
| .lmx | Nokia Landmark Exchange Format |
| .ln | UNIX Lint |
| .lna | Xilinx ISE |
| .lnc | Football Manager Player |
| .lnd | 3D Landscape Data |
| .lnf | Oyoaha Lookandfeel Interface Elements |
| .lng | Language Definition Format |
| .lngx | KeePaas Language |
| .lnk | Windows Shortcut Format |
| .lnm | Corel WordPerfect SGML Alias |
| .lnp | µVision Linker Input Format |
| .lns | AVG Anti-Virus Language |
| .lnst | Adobe InDesign Format |
| .lnt | PC-lint Configuration Format |
| .lnx | Atari Lynx ROM Image Format |
| .lnz | Petz Linez |
| .lo | Interleaf Compiled Lisp Format |
| .loaderbackup | BlackBerry Backup |
| .loaders | GTK+ Loaders Format |
| .loadtest | Microsoft Visual Studio Load Test |
| .lob | IBM DB2 LOBFILE |
| .loc | Localisation String Resource Header Format |
| .local | Delphi User-specific Project Options |
| .localized | MAC OS X |
| .localstorage | WebKit Local Storage Data Format |
| .localstorage-journal | Google Chrome Rollback Journal |
| .lock | Lock Format |
| .lock3 | BlackBerry Encrypted 3GP |
| .lockfile | Mac OS X Lion Property List XML Lock Format |
| .lock_sync | Synchronization Lock |
| .lod | Homeworld Level Of Detail Format |
| .lof | Audacity File List |
| .log | Log Format |
| .log1 | Microsoft Windows Registry Hive Log Format |
| .log2 | Microsoft Windows Registry Hive Log 2 Format |
| .logic | Apple Logic Pro Music Project Format |
| .logikcs | Apple Logic Key Commands |
| .login | UNIX Command |
| .logonvista | Stardock LogonStudio Windows Vista Logon Screen Format |
| .logonxp | LogonStudio Document Format |
| .lok | W32/Rbot-WE Log |
| .lol | Lolcode Source Format |
| .lols | LOLCODE Source Code |
| .lon | Aquaterra Profile Data |
| .look | SpeedGrade Look Format |
| .loop | Apple Soundtrack Pro |
| .loov | Smadav Virus Definitions Format |
| .lop | MasterCook Layout Format |
| .los | Close Combat 2 Map Related |
| .lot | LaTex Auxiliary File For List Of Tables |
| .lov | SAP Business Objects |
| .love | LÖVE Game Package Format |
| .lo_ | Microsoft System Management Server Renamed Old Log |
| .lp | Lightscape 3D Object Format |
| .lp2 | ILEAP Word Processor Document Format |
| .lp4 | 36-Image Converter Encrypted Language Pack |
| .lp7 | LP7Signer Digital Signed Format |
| .lpa | LPA View Laser Particle Analyser |
| .lpaq8 | PAQ Data Archive |
| .lpb | LaserTank Game Replay Format |
| .lpd | Lookout Protocol Driver Format |
| .lpdb | Librarian Pro Database Format |
| .lpdf | Mac OS X Localized PDF (Portable Document Format) Format |
| .lpf | Orgadata LogiKal |
| .lpi | Free Pascal Lazarus Project Information |
| .lpk | ArcGIS Layer Package Format |
| .lpmd | Las Palmeras Molecular Dynamics (LPMD) Data Format |
| .lpn | LVPLAN |
| .lpp | LabelPrint Project Format |
| .lpr | Homeworld |
| .lproj | Mac OS X Localized Project Folder Format |
| .lps | Bryce Leaf Shape Format |
| .lpt | LogPlot Compiled Boring Log |
| .lpu | Passolo Localization Project |
| .lpw | IRIS Laserform Lforms |
| .lpx | LaTeXPiX Script |
| .lqf | LeechFTP Save Queue |
| .lqr | SQ Compressed LBR Archive |
| .lqt | Liquid Audio Liquid Digital Media Music File Format |
| .lr | Chaos Desktop Layer List |
| .lrc | Lyric Format |
| .lrcat | Adobe Lightroom Catalog Format |
| .lrcat-journal | Adobe Photoshop Lightroom |
| .lrd | Microsoft Money Lock |
| .lrdata | Adobe Lightroom Preview Data |
| .lrdb | Photoshop Lightroom Database |
| .lrec | Inter-Tel Web Conference Recording Format |
| .lrf | BBeB Ebook Format |
| .lrg | Macromedia XRes Multi-resolution Bitmap |
| .lrl | SmartWare Local Resource Library |
| .lrm | Microsoft Encarta Class Server Learning Resource |
| .lrn | Apple Chess User Data |
| .lrp | IBM Works For OS/2 Report |
| .lrplugin | Adobe Photoshop Lightroom Plug-in Format |
| .lrprev | Adobe Photoshop Lightroom Index |
| .lrs | BBeB Ebook Source Format |
| .lrsmcol | Adobe Photoshop Lightroom Settings Format |
| .lrtemplate | Adobe Photoshop Lightroom Preset Settings Format |
| .lrtoolkit | Adobe Photoshop Lightroom |
| .lrv | Low Resolution Video Format |
| .lrwebengine | Lightroom Folder |
| .lrx | BBeB Ebook Format |
| .lry | Konica Minolta Data Management Software Reference Data |
| .ls | LightWave LScript Format |
| .ls1 | Microsoft Winhelp Source |
| .ls3 | Band-in-a-Box Style Format |
| .ls4 | Lumion Exported Full Scene |
| .lsa | Lotus Designer Agent |
| .lsaprototype | Microsoft Visual Studio Logical Datacenter Diagram Toolbox Prototype |
| .lsc | LOGO! Soft Comfort |
| .lsd | FIFA World Cup Game Data Environment Format |
| .lsf | Advanced Streaming Format |
| .lsl | Corel Paradox Format |
| .lslibrary | Littlesnapper User Library Package |
| .lsm | Ziess LSM Model |
| .lsn | Microsoft Works Format |
| .lso | Apple Logic Song Format |
| .lsp | LISP Source Code Format |
| .lsproj | Visual Studio LightSwitch Project |
| .lsq | IBM Voice Type Languages Addword |
| .lsr | LANsurveyor Report Format |
| .lss | LotusScript Source Code |
| .lst | List Text Format |
| .lstx | E-Sword Verse List |
| .lsu | LANsurveyor Map Format |
| .lsv | Light-O-Rama Sequence Editor Visual Preference |
| .lsw | RPG Maker Saved Game Format |
| .lsx | Advanced Streaming Redirector Format |
| .lsz | Learning Score Zip |
| .ls_ | Unix Ls Directory |
| .lt2 | Poser Light Set Format |
| .lta | Monolith Lithtech Game Engine |
| .ltb | Amma Little Setup Builder |
| .ltc | LTC Syntactically Analyzed Text |
| .ltcx | LTC Syntactically Analyzed Text XML |
| .ltd | LivingTime Data |
| .ltf | Frogans Short-cut Format |
| .ltg | LaserTank Graphics Format |
| .lth | Roxio Label Creator Style |
| .ltkey | LeaderTask Key |
| .ltl | DIALux Luminaire Data |
| .ltm | IBM Lotus Forms Form |
| .ltr | Letter Format |
| .lts | Links Email Tourney |
| .ltt | HP Library And Tape Tools Log |
| .ltx | LaTeX Document Format |
| .ltz | Poser Compressed Light Set Format |
| .lua | Lua Script Format |
| .luac | Lua Compiled Source Code |
| .luar | UltraDefrag Lua Report |
| .luca | Luca Template |
| .lucs | Amaya Tools |
| .lud | CARE-S InfoWorks Land Use |
| .lue | Norton LiveUpdate Log Format |
| .luf | Lipikar Uniform Format |
| .lug | Game |
| .lum | Luminous Song List |
| .lut | XnView Lut Format |
| .lutx | RadioRA Essentials Database Format |
| .luv | Medieval 2 Total War |
| .luxb | Lux Delux Map Format |
| .luz | Spectramap |
| .lv6 | Return To Wonderland Level |
| .lva | Logitech Video Effects Avatar Format |
| .lvb | Outlaws Game |
| .lvclass | LabVIEW Class Library |
| .lvd | LabelPro Design Document |
| .lvf | Logitech Video Effects Avatar And Face Accessory |
| .lvivt | Lvivtotoro Game Format |
| .lvix | Lightworks Video Index |
| .lvl | Game Level Format |
| .lvlib | LabVIEW Project Library |
| .lvlibp | LabVIEW Packed Project Library |
| .lvlps | LabVIEW Local Project Settings |
| .lvm | LabVIEW Measurement Format |
| .lvp | Avaya Voice Player Compressed Voice Audio |
| .lvr | Microsoft Visual Studio Environment Snapshot |
| .lvw | Livewire Document Format |
| .lw | LightWave 3D Binary |
| .lw2 | Lightwright Show Data |
| .lw3 | Lightwright Data |
| .lw4 | Lightwright 4 Show Data Format |
| .lw5 | Lightwright Show Data |
| .lwa | Lightwright Automated Action |
| .lwac | Likno Web Accordion Builder |
| .lwbm | Likno Web Button Maker |
| .lwc | Legacy Charting Chart |
| .lwd | LotusWorks Text Document |
| .lwf | LuraWave Format Image Format |
| .lwfn | Adobe Type 1 Font |
| .lwi | Light Work Image Image Format |
| .lwk | Siemens NX Software Graphics |
| .lwl | Lightwright Printed Paperwork Formatting Instructions |
| .lwlo | LightWave Layered Object |
| .lwm | LittleWays Map |
| .lwmw | Likno Web Modal Windows Builder |
| .lwo | LightWave Object Format |
| .lwob | LightWave 3D Object |
| .lwp | Lotus Word Pro Document Format |
| .lwpp | Live Wallpaper For Mac Desktop Theme |
| .lwq | SWAT Lake Water Quality Input |
| .lws | LightWave Scene Format |
| .lwt | Lightwright Attribute List |
| .lwtb | Likno Web Tabs Builder |
| .lwtp | LimeWire Theme Format |
| .lwtt | Likno Web Tooltips Builder |
| .lwv | Microsoft Linguistically Enhanced Sound Format |
| .lwx | Lightwright Database |
| .lwz | LightWave 3D Plugin |
| .lxa | Microsoft Speech Engines Lexicon Format |
| .lxcp | LCARS X32 For Windows Color Profile Format |
| .lxd | EDictionary Reader Dictionary Data |
| .lxf | LEGO CAD Scene Format |
| .lxfml | LEGO Digital Designer XML Format |
| .lxk | COREX Lexicon Link-up |
| .lxl | Luxology Modo Single-layer Mesh Presets |
| .lxo | Luxology Modo 302 3D Drawing Format |
| .lxsopt | Liquid XML Studio Project Settings Format |
| .lxsproj | Liquid XML Studio Project Format |
| .lxt | S.T.A.L.K.E.R. |
| .lxv | Lexar Secure II Encrypted Archive |
| .ly | LilyPond Music Score Format |
| .lyc | BestIMAGE Compressed Drawing Format |
| .lyr | ArcView Layer Format |
| .lys | DataCAD Layer Control |
| .lyt | DESQview Format |
| .lyx | LyX Document Format |
| .lz | LZIP Compressed Archive Format |
| .lzc | Need For Speed Undercover Game Data |
| .lzf | Autodesk 3D Studio Max Lens Effect Flare |
| .lzh | LH ARC Compressed Archive Format |
| .lzk | LoizziTimeControl Database |
| .lzm | Slax Module Format |
| .lzma | 7-zip Compressed Format |
| .lzma86 | Archive |
| .lzo | Lzop Archive Format |
| .lzop | LZOP Compressed |
| .lzp | Law And Order 3: Justice Is Served Game |
| .lzs | Compressed File Archive |
| .lzx | Amiga LZX Archive Format |
File extensions are not normally displayed to users. To change this, go to Control Panel, select Appearance and Personalization and Folder Options. Next, select the View and find the option "Hide extensions for known file types". The option should be deselected (cleared) and confirmed with OK.
