FS File Extension
Visual F# Source Format
- File Type fs
- Developer Microsoft
- Popularity
- Application Notepad++
- Category Developer Files
- Format Text
What is a FS file?
The FS extension is related to Visual F# Source Format and is classified in the Developer Files category, which contains 1166 files.
Microsoft, the developer of the Visual F# Source Format (FS), has released file format and 242 programs designed to handle them.
FS file support extends to various operating systems, including Windows, Linux and Mac OS. There are 5 programs available to open a FS file, including popular tools like Microsoft Visual Studio, Notepad++ and Sublime Text.
Programs that support FS files
How to open a FS file?
If you are having trouble opening a FS file, it usually means the right software is not installed. Choose a program from the list that matches your operating system. Next, visit the official website of the developer, download the software, and install it on your device.
Thanks to their popularity, Microsoft Visual Studio, Notepad++ and Sublime Text are often the go-to programs for managing FS files. If you want the most recent release of Notepad++, head over to the Notepad++ Team site and download the version designed to run on all platforms.
After completing the installation, FS files should be recognized by the system and linked to Notepad++.
Set Notepad++ as your default FS viewer
Set default app to open files on Mac
- Right-click or Control + left-click on the desired FS file to open a menu of available actions;
- Choose "Open in Application" and click "Other";
- In the lower section of the window, you’ll find the "Enable" menu, with "Recommended Programs" pre-selected as the default option;
- Select "All Programs" in this menu, and then search for Notepad++. Check the box next to "Always open in app" to make sure it’s the default option.
Change a default app in Windows
- To get started, right-click your FS file, then choose "Open With" and select "Choose Another Application" from the context menu;
- From the list of applications in the pop-up window, find and select Notepad++ as your desired application;
- Check the "Always use this app" checkbox, and then click "OK" to set your chosen app as the default for opening FS files.
Solving Common FS File Challenges
While FS files can sometimes present difficulties, most problems can be resolved quickly with minor software modifications. Check the tips below to help solve them.
What Causes Notepad++ to Crash Frequently?
Insufficient software updates are a likely cause of Notepad++ crashes. Be sure to install the latest updates for Notepad++ Team products.
A simple restart of your computer can often fix many common problems, which is why it is the recommended first step before making any adjustments to your software settings.
How can I restore a damaged FS file?
Start a data recovery program and open the damaged FS file. Then, choose the "Repair" option from the menu. Allow the recovery process to complete, which will automatically repair the damaged developer files.
How can I determine if my FS file is damaged?
Characteristics of corrupted FS developer files can include:
- Notepad++ or other programs stop responding or crash when trying to handle the file;
- Error notifications appear during file manipulation;
- When opening the file, errors occur or the inability to access its contents;
- Unexplained FS file size inflation;
- Editing the archive in Microsoft Visual Studio is hampered by poor overall performance;
How to edit a FS file?
To modify FS files, you need to install special software that makes it possible to open and edit developer files. Online FS editors are more restricted compared to software designed for Visual F# Source Format.
Best FS Editor Software in 2026
Taking the above factors into account, we have selected a list of FS editors currently available.
| FS Editor Software | Developer | Platforms | Overall Rating |
|---|---|---|---|
| PSPad | Jan Fiala | Windows | 4.7 out of 5 (41 review) |
| Notepad++ | Notepad++ Team | Windows | 4.6 out of 5 (37 reviews) |
| Sublime Text | Sublime HQ Pty | Windows, Mac OS, Linux | 4.6 out of 5 (39 reviews) |
| Microsoft Visual Studio | Microsoft | Windows, Mac OS, Linux | 4.2 out of 5 (35 reviews) |
| Atom | - | Windows, Mac OS, Linux | 4.1 out of 5 (36 reviews) |