File extensions beginning with the letter U. Commonly used extensions are listed in bold.

	U  A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z .u Unreal Tournament Class Package (more info) .u AU Audio File (more info) .u Subsampled Raw YUV Image (more info) .u3d Universal 3D File (more info) .u3i U3 Application Information File (more info) .u3p U3 Smart Application (more info) .uax Unreal Audio Package (more info) .ub Unsigned Byte Audio File (more info) .uc UnrealScript Class (more info) .uc2 UltraCompressor 2 Archive (more info) .uci UFS Explorer Backup File (more info) .ud OmniPage User Dictionary (more info) .udb Dynamics AX User Database File (more info) .udf Excel User Defined Function (more info) .ufo Ulead File Object (more info) .uha UHarc Compressed Archive (more info) .ui User Interface File (more info) .uibak UltraISO Backup Disk Image (more info) .uif Universal Image Format Disc Image (more info) .uis WindowBlinds User Interface Specification (more info) .ukx Unreal Animation Package (more info) .ulaw Raw u-Law Audio File (more info) .ulf Universal List File (more info) .uls NetMeeting User Location Service File (more info) .ult UltraTracker Module (more info) .ulw u-Law Audio File (more info) .ulz USBlyzer Data Capture File (more info) .umod Unreal Tournament Module File (more info) .umx Unreal Music Package (more info) .unauth SiteMinder Unauthorized Message File (more info) .uni MikMod UniMOD Module (more info) .unity3d Unity Web Player File (more info) .unk Unknown File (more info) .unknown Unknown File Type (more info) .unr Unreal Level Map (more info) .unx Unix Text File (more info) .uop Ultima Online Patch File (more info) .upd Program Update Information (more info) .upoi iGO Points of Interest File (more info) .url Internet Shortcut (more info) .urt Utah Raster Toolkit File (more info) .usa Unreal Saved Game File (more info) .usf Nintendo 64 Music File (more info) .usflib Nintendo 64 Song Library (more info) .usx Unreal Static Meshes (more info) .ut2 Unreal Tournament Map (more info) .ut2mod Unreal Tournament 2003/2004 Module File (more info) .ut3 Unreal Tournament 3 Map File (more info) .utc Bioware Creature File (more info) .utf8 Unicode UTF8-Encoded Text Document (more info) .utx Unreal Texture Package (more info) .utxt Unicode Text File (more info) .uu Uuencoded File (more info) .uud UUDecoded File (more info) .uue Uuencoded File (more info) .uvf Uncertain Value Format (more info) .uvx Unreal Tournament 2003 Saved Game (more info) .uw Unsigned Word Audio File (more info) .uwf UltraTracker Wave File (more info) .uxx Unreal Tournament Cache (more info)

All File Extensions | "U" Computer Terms

Looking for a file extension that isn't listed here? Send in your suggestion!

Other Help Center Resources:

Computer Questions and Answers | List of Domain Suffixes