File types with extensions that start with the letter U

File Extention	File Type	Description
.u	Audio	AU Audio File
.u	Game	Unreal Tournament Class Package
.u	Raster Image	Subsampled Raw YUV Image
.u10	Data	UFile 2010 Tax Return
.u11	Data	UFile 2011 Tax Return
.u12	Data	UFile 2012 Tax Return
.u3d	3D Image	Universal 3D File
.u3i	Text	U3 Application Information File
.u3p	Executable	U3 Smart Application
.u8	Audio	3D Lemmings Audio File
.uax	Audio	Unreal Audio Package
.ub	Audio	Unsigned Byte Audio File
.ubj	Data	Universal Binary JSON File
.ubox	Data	Universe Sandbox Data File
.uc	Game	UnrealScript Class
.uc2	Compressed	UltraCompressor 2 Archive
.uccapilog	Data	Microsoft UCC API Log File
.uce	System	Windows UCE System File
.ucf	Web	WebEx Media File
.uci	Backup	UFS Explorer Backup File
.ucl	Game	Killing Floor System File
.ucm	Game	Crazy Machines Model File
.uct	Settings	UC Browser Theme File
.ud	Data	OmniPage User Dictionary
.udb	Database	Dynamics AX User Database File
.udc	Data	Adobe InDesign User Dictionary
.udcx	Settings	Universal Data Connection File
.udeb	Data	Debian Package File
.udf	Executable	Excel User Defined Function
.udf	Disk Image	Universal Disk Format File
.udk	Game	Unreal Engine Map File
.udl	Database	Microsoft Universal Data Link File
.uds	Misc	NetBackup UNIX Domain Socket File
.uds	Data	Sierra Generations File
.uds	Data	Uniform Data System File
.uea	Encoded	Protector Suite QL Encrypted Archive
.ufo	Raster Image	Ulead File Object
.ufr	Vector Image	Ultra Fractal File
.ufs	Disk Image	FreeBSD Unix File System File
.ufs.uzip	Compressed	Compressed Unix File System File
.uga	Raster Image	Ulead GIF Animator File
.uha	Compressed	UHarc Compressed Archive
.uhtml	Web	UC Browser Saved Webpage
.ui	Developer	User Interface File
.uibak	Disk Image	UltraISO Backup Disk Image
.uif	Disk Image	Universal Image Format Disc Image
.uis	Settings	WindowBlinds User Interface Specification
.ukx	Game	Unreal Animation Package
.ulaw	Audio	Raw u-Law Audio File
.ulf	Data	Universal List File
.uls	Misc	NetMeeting User Location Service File
.ult	Audio	UltraTracker Module
.ulw	Audio	u-Law Audio File
.ulz	Data	USBlyzer Data Capture File
.umd	Game	Splinter Cell Blacklist Game Data File
.umf	Data	MediaHolder Universal Media Format File
.uml	Developer	UML Data Object Model
.umlclass	Developer	UML Class Model
.umod	Game	Unreal Tournament Module File
.ums	3D Image	Rune 3D Mesh File
.umx	Game	Unreal Music Package
.unauth	Text	SiteMinder Unauthorized Message File
.uni	Audio	MikMod UniMOD Module
.unity	Game	Unity Scene File
.unity3d	Game	Unity Web Player File
.unitypackage	Data	Unity Package File
.unityproj	Game	Unity 3D Project
.unk	Misc	Unknown File
.unknown	Misc	Unknown File Type
.unl	Misc	Garmin Unlock File
.unr	Game	Unreal Level Map
.unt	CAD	AutoCAD Unit Definition File
.unx	Text	Unix Text File
.uof	Text	Uniform Office Document
.uop	Data	Uniform Office Presentation
.uop	Game	Ultima Online Patch File
.uos	Spreadsheet	Uniform Office Spreadsheet
.uot	Text	Uniform Office Document
.upd	Text	Program Update Information
.update	Data	ISAPI Update File
.updatr	Game	iConomy Update File
.upf	CAD	Unified Power Format File
.upf	Settings	MicroStation User Preferences File
.upg	Misc	Upgrade File
.upk	Game	Unreal Engine 3 Package
.upoi	Data	iGO Points of Interest File
.upr	Data	FileMaker User Dictionary
.upr	Data	Fractal Parameters File
.upx	Executable	Ultimate Packer for eXecutables File
.uqm	Game	The Ur-Quan Masters Game Data File
.url	Web	Internet Shortcut
.urr	Misc	Uniface Signatures File
.urt	Raster Image	Utah Raster Toolkit File
.usa	Game	Unreal Saved Game File
.useq	Data	USeq Genome Data File
.user	Settings	Visual Studio Project User Options File
.userprofile	Settings	Norton Antivirus User Profile File
.usertile-ms	Raster Image	Windows 8 User Tile File
.usf	Settings	EVGA Precision X Skin File
.usf	Video	Universal Subtitles Format File
.usf	Audio	Nintendo 64 Music File
.usflib	Audio	Nintendo 64 Song Library
.usm	Video	USM Game Video File
.usr	Data	SmartMusic Custom File
.usr	Database	FileMaker Pro Database File
.ust	Audio	UTAU Sequence Text File
.ustar	Data	Uniform Standard Tape Archive Format File
.usx	Game	Unreal Static Meshes
.ut2	Game	Unreal Tournament Map
.ut2mod	Game	Unreal Tournament 2003/2004 Module File
.ut3	Game	Unreal Tournament 3 Map File
.ut4mod	Game	Unreal Tournament 2004 Module
.ut8	Game	Ghost Master Language File
.utc	Game	Bioware Creature File
.utf8	Text	Unicode UTF8-Encoded Text Document
.utw	Game	Unity Whirld File
.utx	Game	Unreal Texture Package
.utxt	Text	Unicode Text File
.utz	Settings	UIQ Theme Package
.uu	Encoded	Uuencoded File
.uud	Encoded	UUDecoded File
.uue	Encoded	Uuencoded File
.uvf	Data	Uncertain Value Format
.uvw	Data	UVW Coordinates File
.uvx	Game	Unreal Tournament 2003 Saved Game
.uw	Audio	Unsigned Word Audio File
.uwf	Audio	UltraTracker Wave File
.uwl	Data	User Word List File
.uxx	Game	Unreal Tournament Cache
.uzip	Compressed	FreeBSD Compressed Disk Image