Where is the FSX installation folder on Windows?

Boxed Microsoft Flight Simulator X (FSX) normally installs to C:\Program Files (x86)\Microsoft Games\Microsoft Flight Simulator X on 64-bit Windows. FSX: Steam Edition (FSX SE) normally uses C:\Program Files (x86)\Steam\steamapps\common\FSX. Custom Steam libraries can be elsewhere; the correct root folder directly contains fsx.exe and folders such as SimObjects, Gauges and Addon Scenery.

What are the default FSX installation paths?

The default location depends on the FSX edition, Windows architecture and any custom folder selected during installation.

Boxed FSX appearing under Program Files (x86) is normal. FSX is a 32-bit application, even when it runs on 64-bit Windows.

How do I find the exact FSX folder?

Steam’s local-files command is the quickest reliable method for FSX SE; boxed FSX can be traced through its shortcut or running process.

1. For FSX: Steam Edition: open your Steam Library, right-click FSX, open Properties, select Installed Files, then use Browse. The folder that opens is the installation root containing fsx.exe. Our Steam Edition add-on workflow explains what to do with this folder next.
2. For boxed FSX: right-click the shortcut and select Properties. Read the Target field; the directory before \fsx.exe is the installation root.
3. If FSX is already running: open Task Manager, find fsx.exe under Details, right-click it and select Open file location.
4. As a fallback: search your drives for fsx.exe. If several copies appear, use the one launched by your normal shortcut and surrounded by the standard FSX folders.

File Explorer may hide known extensions. In that case, fsx.exe can appear simply as fsx, with its file type shown as an application.

How can I confirm that it is the correct folder?

The genuine FSX installation root is the directory that directly contains fsx.exe.

• It should also contain folders including Addon Scenery, Effects, Gauges, Missions, SimObjects and Sound.
• Do not select the parent Microsoft Games, common or SteamLibrary directory when an installer requests the FSX root.
• Do not select SimObjects\Airplanes unless the prompt specifically requests the aircraft folder.

The similarly named folder under %APPDATA%\Microsoft\FSX is not the installation directory. It stores per-user settings such as fsx.cfg; depending on installation history, Steam Edition may instead use a profile folder named FSX-SE. Our guide to finding and safely editing the separate FSX.cfg file explains that distinction.

Likewise, Flight Simulator X Files under Documents contains saved flights and related user files, not fsx.exe.

What if FSX isn’t there or fsx.exe is missing?

If the expected folder is not there, FSX was probably installed in a custom location, moved, removed or never installed on that Windows installation.

• Steam Edition: use Steam’s Browse command rather than guessing the library drive. If the game is not installed, Steam will not be able to open its local folder.
• Boxed FSX: check the shortcut target and search every local drive for fsx.exe. A shortcut that reports a missing target may point to a folder that was moved or deleted.
• Folders exist but fsx.exe does not: the installation is incomplete or the executable has been removed. Do not download a loose replacement fsx.exe.

For FSX SE, Steam’s file-verification command can restore missing stock files. Be aware that verification may also replace stock files modified by add-ons, so preserve any deliberate edits first. For boxed FSX, use the original installation media’s repair option or reinstall to a known location.

There is no setup file — is the installation incomplete?

No. An installed copy of FSX is identified by fsx.exe, not setup.exe; the setup programme belongs to the installation media or installer and does not need to remain in the FSX root.

If an downloaded add-on has no setup file, it is probably a manual-install package rather than a broken download. Extract it first, read any included instructions, and preserve its folder structure instead of dropping the unopened archive or its outer wrapper folder into FSX. Our folder-by-folder instructions for manually installing FSX add-ons cover aircraft, scenery, gauges and effects.

Where should an add-on installer point?

When an installer asks for the FSX directory, select the folder containing fsx.exe, even when the package being installed is an aircraft.

A mistake we see constantly is choosing SimObjects\Airplanes when the installer expects the root. The installer then adds its own SimObjects\Airplanes path underneath, creating duplicated folders and an aircraft that never appears in the simulator.

• “FSX folder”, “main directory” or “installation path”: select the folder containing fsx.exe.
• “Aircraft folder” or “Airplanes folder”: select FSX\SimObjects\Airplanes.
• A simple manual aircraft package: follow the included structure rather than assuming every file belongs in one directory. See our explanation of the correct aircraft and installer destinations.

Why does an add-on installer say FSX is not installed?

If FSX launches but an installer cannot detect it, the usual cause is outdated installer detection or missing installation information in the Windows registry—not an absent simulator folder.

1. Run FSX once: reach the main screen, close it normally, then try the installer again. This creates the per-user files expected by some add-ons.
2. Browse manually: if the installer provides a folder selector, point it directly to the directory containing fsx.exe.
3. Choose the correct edition: select FSX: Steam Edition when offered. Some older installers recognise only boxed FSX and reject a valid Steam folder.
4. Avoid guessed registry changes: boxed FSX and FSX SE use different installation information. Repairing or reinstalling the relevant edition is safer than creating unverified registry entries.

Windows may request administrator permission because the default FSX paths are below Program Files. Files written by an old, non-elevated installer may instead appear under %LOCALAPPDATA%\VirtualStore; that is a compatibility redirection location, not the real FSX installation root.