FSG File

What are FSG files and how to open them

Are you having problems opening a FSG file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your FSG files.

What is a FSG file?

A .FSG file is a Kingsoft Antivirus Data file.

Kingsoft Antivirus Data files with the extension .FSG are used by Kingsoft Antivirus (a security/antivirus application) to store its internal data. These files are created and maintained by Kingsoft Antivirus to support its operations such as virus scanning, threat definitions, or other security features. Users do not normally create or edit .FSG files directly; the program reads from and writes to them as part of its own data management.

These files are typically found in the "data" folder of Kingsoft Antivirus's installation directory and are necessary for the antivirus engine to function correctly. Deleting or modifying a .FSG file may cause Kingsoft Antivirus to malfunction, lose security definitions, or become unstable. There is no known user interface to open them safely, as they are not standard documents or media files.

Technically, a Kingsoft Antivirus Data (.FSG) file begins with a byte signature at the start of the file: the first bytes (at offset 0) are 4B 41 45 66 73 6B 73 67 00 00 01 00, which in ASCII reads "KAEfsk sg" (with trailing nulls and control data). This signature helps tools like TRiD identify the file type.

How to open FSG files

We have identified one FSG opener that is compatible with this specific type of FSG file.

Programs that open Kingsoft Antivirus Data files

Last updated: August 6, 2026

Various apps that use files with this extension

These apps are known to open certain types of FSG files. Remember, different programs may use FSG files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about FSG file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.