Where is the FSX.cfg file in Windows 10 or 11?

On Windows 10 or 11, boxed Microsoft Flight Simulator X normally stores FSX.cfg at %APPDATA%\Microsoft\FSX\FSX.cfg. FSX: Steam Edition may use that same path or %APPDATA%\Microsoft\FSX-SE\FSX_SE.cfg. Paste %APPDATA%\Microsoft into File Explorer, then check both folders; the active configuration is not normally in the FSX installation directory.

FSX.cfg locations for boxed FSX and FSX: Steam Edition

The correct FSX.cfg location depends on the edition and the user-profile layout created when Steam Edition was first run.

Steam Edition often retains the original FSX folder and filename when it is the only FSX edition installed. If boxed FSX was detected, Steam Edition can create the separate FSX-SE profile instead. Previous installations can leave either layout behind, so installation history matters more than where Steam itself is installed.

%APPDATA% represents the roaming application-data folder for the signed-in Windows user. It usually expands to C:\Users\your-name\AppData\Roaming, but the environment-variable path remains correct if Windows or the user profile is stored elsewhere. For documentation or support notes, use the %APPDATA% form rather than another user's literal profile path.

Do not confuse this user configuration with the folder containing fsx.exe, aircraft and add-ons. Our explanation of how to find the separate FSX installation directory covers that location.

How do I open FSX.cfg when AppData is hidden?

The quickest method is to use the Windows %APPDATA% shortcut, which opens the correct user profile without requiring hidden folders to be displayed.

1. Close FSX completely. Editing the file while the simulator is running risks having your changes overwritten when it exits.
2. Press Windows key + R. This opens the Run box.
3. Enter %APPDATA%\Microsoft and press Enter.
4. Open the relevant folder. Check FSX first, then FSX-SE if it exists.
5. Show filename extensions. Use File Explorer's View controls to enable file name extensions, then look for FSX.cfg or FSX_SE.cfg.

When known extensions are hidden, Windows may display FSX.cfg simply as FSX. Searching from the Start menu is less reliable because files under hidden AppData folders may not be indexed.

FSX.cfg is not there — why do I not see the file?

If FSX.cfg is not there, FSX may not yet have created a configuration for that Windows account, or you may be looking at the wrong profile.

• Launch the required FSX edition, allow it to reach its main screen, then close it normally. This should create or update its configuration.
• Check both %APPDATA%\Microsoft\FSX and %APPDATA%\Microsoft\FSX-SE.
• Confirm that you are using the same Windows account that runs FSX. If you entered credentials for another administrator account, that account has separate AppData folders.
• Enable filename extensions. A file shown as FSX may already be FSX.cfg.
• Do not search only the FSX installation folder, Documents or Program Files; the global user configuration does not normally belong there.

Do not create an empty configuration manually. If FSX crashes before reaching its menu or cannot create its profile, work through our FSX startup checks for Windows 10 and 11 and then let the simulator generate the file.

Which FSX configuration file is active?

The active file is the one whose modification time changes after your edition of FSX saves a setting.

1. Close both editions and note the modification times of any FSX.cfg and FSX_SE.cfg files.
2. Start FSX normally using the same shortcut and Windows account you usually use.
3. Change one harmless setting, apply it, and exit the simulator normally.
4. Refresh both folders and identify the file with the new modification time.

A mistake we see constantly is editing an old boxed-FSX configuration while Steam Edition is reading FSX_SE.cfg. A matching file copied into a backup or installation folder is not active merely because it has the right name.

If neither file changes, FSX may be unable to write to the profile, or a different Windows account may be involved. Use our guide to diagnosing settings and saved flights that FSX will not retain.

Why does nothing change after I edit FSX.cfg?

When nothing changes, the usual causes are an inactive profile, a hidden .txt extension, or an edit made while FSX was still running.

• Wrong profile: confirm the active file with the modification-time test above.
• Wrong extension: Notepad may create FSX.cfg.txt; FSX will ignore it.
• FSX was open: the simulator can overwrite the edited file when it closes. Always exit first.
• Wrong section or spelling: a valid setting placed under the wrong bracketed section may be ignored or removed.
• The setting belongs elsewhere: aircraft, scenery and some add-ons use their own configuration files rather than the global FSX.cfg.
• The tweak has no applicable effect: lines copied from old tweak lists may be hardware-specific, ineffective or already represented by an in-simulator setting.

Can I edit or reset FSX.cfg safely?

You can edit or rebuild FSX.cfg safely if FSX is closed and you preserve the original file first.

1. Make a backup outside the active folder, or rename the file to FSX.cfg.bak or FSX_SE.cfg.bak.
2. Edit only as plain text and retain the original .cfg extension. Change one item at a time so that an error is easy to reverse.
3. Reset it when necessary by leaving the renamed backup in place and launching FSX. The simulator should create a fresh configuration with default settings.

Rebuilding the file does not uninstall aircraft or scenery, but it resets preferences and can remove stored trust records for add-on modules. Our step-by-step FSX.cfg editing and reset instructions explain the backup and recovery process without replacing your configuration with a generic file from another computer.