Most commonly found extensions (PART 1: Q to S):

.QIC Windows backup file

.QT Quick Time Movie File

.QXD Quark Express file

.QXL Quark Xpress element library

.QXT Quark Xpress template file

.RA Real Audio file.

.RAM Real Audio file.

.RAR Compressed file similar to .ZIP uses different compression program to extract. See our recommended download page for a program that can be used to extract .RAR files.

.RAS File extension used for raster graphic files.

.RD1 Descent registered level file

.RD3 Ray Dream designer graphics file / CorelDraw 3D file

.RD4 Ray Dream designer graphics file

.RD5 Ray Dream designer graphics file

.RDB TrueVector rules database

.RDF Resource description framework file / Chromeleon report definition

.RDL Descent registered level file / RadioDestiny radio stream

.RDX Reflex data file

.REC Sound file used with Windows Sound Recorder.

.RLE Microsoft Windows Run Length Encoded (Run Length Encoded (bitmap format) file that contains the actual screen logo).

.RMI Microsoft RMID sound file.

.RPB Automotive diagnostic file.

.RPD Rapidfile database

.RPM Red Hat Package Manager / RealMedia Player file.

.RPT Various Report file

.RTF Rich Text Format file

.RWZ Microsoft Outlook rules wizard file

.SAV File that usually contains saved information such as a saved game.

.SC2 Maps used in Sim City 2000.

.SCP Dialup Networking script file.

.SCR Source files for the .INI files, or sometimes may be used as screen savers.

.SD Sound Designer I audio file

.SD2 Sound Designer II flattened file / Sound Designer II data fork file / SAS database file

.SDA StarOffice drawing file / SoftCuisine data archive

.SDC StarOffice spreadsheet

.SDD StarOffice presentation

.SDF Standard data format file / Schedule data file / System file format / Autodesk mapguide spatial data file

.SDK Roland S-series floppy disk image

.SDL SmartDraw library

.SDN Small archive

.SDR SmartDraw drawing

.SDS StarOffice chart file / Raw MIDI sample dump standard file

.SDT SmartDraw template

.SDV Semicolon divided value file

.SDW Sun Microsystems StarOffice file document file similar to the Microsoft Office .DOC file.

.SDX MIDI sample dump standard files compacted by SDX

.SEA Short for Self Extracting Archive. Compressed file used with the Macintosh.

.SH Archive file

.SH3 Harvard (now Serif) presentation file

.SHB Corel Background file

.SHG Hotspot Editor Hypergraphic

.SHK Macintosh Compressed Archive file

.SHM WordPerfect Shell Macro

.SHP 3D Studio Shapes File / other 3D related file

.SHR Archive file

.SHS Shell scrap object file

.SHW Corel presentation / WordPerfect Slide Show / Show File

.SLK Multiplan file.

.SND Sound Clip file / Raw unsigned PCM data / AKAI MPC-series sample / NeXT sound / Macintosh sound resource file

.SNG MIDI song

.SNM Netscape Mail

.SNO SNOBOL program file

.SNP Snapview snapshot file

.SUM Summary file.

.SWF Macromedia Flash file.

.SWP Extension used for the Windows Swap File usually Win386.Swp. This file is required by Windows and generally can grow very large in size sometimes up to several hundred megs. This file is used to swap information between currently running programs and or memory. If this file is deleted from the computer Windows will be unable to load and will need to be reinstalled.

.SYS System and peripheral drivers.