How do I install FS2004 on Windows 11?

Install Microsoft Flight Simulator 2004 (FS2004) on Windows 11 by running setup.exe from Disc 1, choosing a writable folder such as C:\FS2004, applying the official 9.1 update before any add-ons, then attempting the first launch with Disc 4 inserted. If installation finishes but FS2004 will not open, Windows 11's unsupported legacy disc check is usually responsible.

Can FS2004 run on Windows 11?

Yes, FS2004 can usually run on Windows 11, although Microsoft never designed or supported it for this operating system. FS2004 is a 32-bit application, and 64-bit Windows 11 can run the simulator itself; most failures involve its old installer, permissions, full-screen display settings or Disc 4 authentication.

The age of the computer is rarely the problem. A clean base installation is generally straightforward once it is kept outside protected Windows folders and the legacy disc check is dealt with separately.

Before installing FS2004

Prepare the installation media and choose the destination folder before starting setup.

• Use the original four-CD set or a lawful backup. The standard boxed release starts from Disc 1 and normally requests Disc 4 for launching.
• Use a reliable optical drive. An external USB DVD drive is suitable if the computer has no internal drive. Clean visibly dirty discs before installation.
• Choose a fixed local drive. We recommend C:\FS2004 or D:\FS2004, not a network drive, removable drive or OneDrive-managed folder.
• Back up an older installation first. Save any aircraft, scenery, gauges, effects, flight plans and configuration files you intend to keep.

How to install FS2004 on Windows 11 step by step

The safest method is to install the base simulator, update it while its files are still unmodified, and test it before adding anything else.

1. Start setup manually. Insert Disc 1, open the drive in File Explorer and run setup.exe. Autorun often does nothing on Windows 11. If setup closes or reports an access error, right-click it and select Run as administrator.
2. Select a custom destination. Change the proposed location to a simple path such as C:\FS2004. Avoid Program Files and Program Files (x86).
3. Finish the disc installation. Insert each numbered disc when requested and allow setup to complete. A read or cabinet-file error usually indicates damaged media or an unreliable optical drive; do not ignore it and continue with a partial installation.
4. Apply Update 9.1. Install the official FS2004 9.1 update before replacing executables or installing aircraft, scenery and utilities. Version 9.1 is the final Microsoft update and is expected by many FS2004 add-ons.
5. Attempt the first launch. Insert Disc 4 and run fs9.exe from the installation folder. If Windows asks for permission, approve the prompt, but do not enable permanent administrator mode unless testing shows it is necessary.
6. Test a default flight. The first start can take longer while FS2004 creates its configuration and scenery data. Load a default aircraft at a default airport, fly briefly, exit normally and start the simulator again.

Why does FS2004 install but not launch on Windows 11?

A successful installation followed by a Disc 4 request, immediate exit or no visible response usually points to the boxed release's legacy disc authentication rather than damaged simulator files.

Windows 11 does not load the old driver on which this SafeDisc-era check depends. The disc may appear perfectly readable in File Explorer while authentication still fails, so repeatedly reinstalling the simulator rarely changes the result.

Use a no-CD patch in the correct order

A version-matched no-CD replacement allows a legitimately owned installation to start without the unsupported Disc 4 check. It is not an official Microsoft update, and it must match the installed simulator version.

1. Install the unmodified base simulator. Do not replace fs9.exe yet.
2. Apply the official 9.1 update. The updater may reject a previously modified executable.
3. Back up the updated executable. Make a copy of fs9.exe somewhere outside the simulator folder.
4. Install the matching replacement. Use the FS2004 9.1 no-CD patch only after the simulator has been updated to 9.1. A 9.0 replacement and a 9.1 installation are not interchangeable.
5. Test before adding anything. Launch a default flight and close FS2004 normally.

Because a no-CD patch changes an executable, security software may inspect or quarantine it. Do not disable Windows Security permanently or make broad security exclusions merely to force an unknown executable to run.

Should FS2004 be installed outside Program Files?

Yes, a new Windows 11 installation should go in a separate writable folder such as C:\FS2004.

The core simulator can sometimes run from Program Files (x86), but many period add-ons expect to write directly into the FS2004 directory. Windows protects that directory through User Account Control, leading to settings that do not persist, missing gauges or scenery installers that appear to finish without placing files where expected.

If an existing Program Files installation works correctly, there is no need to reinstall it solely because of its location. Reinstall to a custom folder when permissions or add-ons are already causing trouble. Do not disable UAC or grant every user full control over the entire Program Files tree.

Do not drag an installed FS2004 folder to another drive. Old add-on installers often use the registered installation path, so moving the folder without reinstalling can leave the registry and actual location out of step.

Should compatibility mode or administrator mode be enabled?

Try running fs9.exe normally before enabling either option. FS2004 often needs no compatibility setting when installed in its own writable folder.

• Use administrator mode as a diagnostic. If it fixes saved settings or file-access errors, the underlying folder permissions or an old add-on are usually the real issue.
• Apply one compatibility change at a time. Enabling several settings together makes it difficult to identify the useful one and can introduce new display problems.
• Try disabling full-screen optimisations only for display faults. This may help when windowed mode works but full-screen mode produces a black screen or unstable switching.
• Reset the configuration before assuming setup failed. A damaged fs9.cfg can cause an immediate crash or unusable graphics settings.

Where is fs9.cfg on Windows 11?

After the first successful launch, FS2004 normally stores its main configuration file at %APPDATA%\Microsoft\FS9\fs9.cfg.

Paste %APPDATA%\Microsoft\FS9 into the File Explorer address bar to open the folder without exposing hidden files. If FS2004 has never reached its first proper launch, the folder or file may not exist yet.

For troubleshooting, close FS2004 and rename fs9.cfg to fs9.old. The simulator will create a clean configuration on its next start. This resets display, sound and controller settings, but renaming rather than deleting the file preserves a backup.

Common FS2004 installation problems on Windows 11

Most installation and first-launch failures can be narrowed down by when they occur.

For crashes or permission faults that continue after a clean installation, use our broader FS2004 troubleshooting checklist for modern Windows, which covers configuration files, disc checks and add-on isolation in more detail.

What should you do after FS2004 is working?

Keep the simulator clean until it can load and exit a default flight reliably on two consecutive starts.

1. Configure graphics, sound and controls. Make small changes and restart once to confirm that they are being saved.
2. Back up the clean installation. A copy made after the 9.1 update provides original files to restore when an old package overwrites gauges, textures or executables. It does not replace the normal installer or its registry entries.
3. Add one package at a time. Test after each aircraft, scenery or utility installation so a faulty package is easy to identify.
4. Read old add-on instructions carefully. Some FS2004 packages use 16-bit installers that cannot run on 64-bit Windows 11 even though the simulator itself can. That is an add-on installer limitation, not evidence that FS2004 was installed incorrectly.