Home : File Types : FS File (3 File Associations)

.FS File Extension

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File Type 1Visual F# Source File

3.4 (8 Votes) Thanks for voting!
Rare Uncommon Average Common Very Common
CategoryDeveloper Files


This file is saved in a plain text format. You can open and view the contents of this file using a text editor.


Source code file written in Microsoft's F# (pronounced "F Sharp") programming language, which is a variant of the ML language; can be written using the Visual F# component of Microsoft Visual Studio 2010; used for compiling F# code into .DLL or .EXE program executables.

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F# is designed for use with Microsoft's .NET library and tools. It was formally introduced with Microsoft's 2010 release of Visual Studio.

Program(s) that open .FS files
Microsoft Windows LogoWindows
Microsoft Visual Studio 2013
Updated 7/7/2010

File Type 2FlexiSIGN Document

DeveloperSA International
2.5 (2 Votes) Thanks for voting!
Rare Uncommon Average Common Very Common
CategoryVector Image Files


This file is saved in a binary format, which requires a specific program to read its contents.


Image file created by one of SAi's Flexi FAMILY software products; stores the text, graphics, dimensions, and plotting properties for a sign; used for printing banners and other signs on large-scale plotters and cutters; can be exported as a .PDF or .EPS file using the software.

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Flexi FAMILY products include FlexiSIGN, FlexiSIGN-PRO, FlexiEXPERT, FlexiPRINT & CUT, FlexiLETTER, FlexiDESIGNER, FlexiENGRAVE, and FlexiENGRAVE-PRO.

Program(s) that open .FS files
Updated 6/22/2010

File Type 3Mac OS X File System Plug-in

2.3 (3 Votes) Thanks for voting!
Rare Uncommon Average Common Very Common
CategoryPlugin Files


File format categories include Binary, Text, XML, and Zip. The format of this file type has not been determined.


Plugin that enables support for a certain file system in Mac OS X; allows the Mac operating system to recognize hard drives and other media formatted with different file systems.

More Information

Examples of file system plugins include "hfs.fs," "msdos.fs," and "cd9660.fs." Each FS file is saved as a Mac OS X bundle, but is defined as a plugin. They are stored by default in the "/System/Library/Filesystems" directory.

NOTE: FS files should not be opened manually since they are system files.

Program(s) that open .FS files
Mac OS X LogoMac
Apple OS X
Updated 1/13/2015