UAP
User agent profile (Used by wireless telephony applications)
UB
Raw unsigned byte (8-bit) data
UC2
Compressed archive (UltraCompressor II)
UCN
New compressed archive (UltraCompressor II)
UDF
Unique Database (Microsoft Windows NT)
UDF
Image filter (Photostyler)
UDW
Raw unsigned doubleword (32-bit) data
UE2
Encrypted archive (UltraCompressor II)
UFO
Object file (Ulead)
UG
Drawing file (AutoCAD and others)
UHS
Binary file (Universal Hint System)
UI
Espire source code (Geoworks UI Compiler)
UI
User interface file (Sprint)
UIF
Long prompts for Microsoft Windows ((Microsoft WordPerfect for Windows)
UIH
Espire header file (Geoworks UI Compiler)
UL
Audio file (ULAW)
ULAW
(CCITT G.711) audio (US Telephony)
ULD
Uploaded file information (Procomm Plus)
ULT
Music module (MOD) (UltraTracker)
UMB
Backup file (archive) (MemMaker)
UNI
UniMod music module (MOD) (MikMod)
UNI
Datafile (Forcast Pro)
UNX
Text file (Unix specific information)
UPD
Updated program data (Generic)
UPD
Updated program data (dBase)
UPI
Program file (ULead Photo Impact)
UPO
Compiled updated datafile (dBase)
UPX
Saved Image file (ULead Photo Express)
URL
Internet shortcut file (Universal Resource Locator)
USE
Source Integrity file (MKS)
USP
Printer font w/updated USACII extended character set (Pagemaker)
USR
User database file (Procomm Plus)
USR
Audit trail file (Pro/Engineer)
USR
User database file (Turbo C++)
USR
User database file (Tour)
UU
UU-encoded file
UU
Compressed ASCII archive (UUDE/ENCODE)
UUE
Executable compressed ASCII archive (UUDE/ENCODE)
UUE
UU-encoded file
UW
Raw unsigned 16-bit) datafile (Word)
UWF
Wave file (UltraTracker)