How do I fix FSX after a Windows 10 or 11 update?

To fix boxed FSX or FSX: Steam Edition after a Windows 10 or 11 update, restart Windows, test with a fresh FSX.cfg, reinstall the proper graphics driver, and restore legacy DirectX components. Check security quarantines, activation and add-ons before repairing the simulator or rolling back Windows.

Why can a Windows update stop FSX working?

Windows Update rarely damages FSX itself; it more often changes a driver, security rule, runtime component or permission on which the simulator depends. The exact symptom points to the part that needs repairing.

If the update merely coincided with the failure and none of these symptoms fits, use our full FSX-on-modern-Windows diagnostic path to isolate launch, configuration and installation faults.

Fix FSX after Windows Update in this order

1. Complete the update and restart Windows. Use Restart rather than shutting down and turning the PC back on, because a restart clears more of the pending update state. Check Windows Update history and record whether Windows installed a system, security or display-driver update, but do not uninstall anything yet.

2. Check Windows Security protection history. Restore an FSX executable, gauge or add-on file only when you recognise its source and are confident it is a false positive. Do not disable protection or exclude the entire FSX drive; if an exclusion is genuinely needed, restrict it to the affected trusted file or folder.

3. Make FSX build a clean configuration. Press Windows+R, enter %APPDATA%\Microsoft, and open the FSX folder. A side-by-side boxed and Steam installation may instead give Steam Edition an FSX-SE folder.

   Rename FSX.CFG to FSX.CFG.old, then start FSX. If the simulator works, reapply settings manually rather than copying the whole old file back. For a black fullscreen window, press Alt+Enter and test in windowed mode.

4. Repair the graphics driver and shader cache. Windows Update can substitute a different display driver even when FSX itself has not changed. Install a stable driver intended for the installed GPU, or use the driver's rollback option if the failure began immediately after a driver update.

   Then open %LOCALAPPDATA%\Microsoft, find the relevant FSX or FSX-SE folder, and rename the Shaders and Shaders10 folders if present. FSX recreates these caches at the next launch. A fresh configuration also turns off settings such as DirectX 10 Preview that may be involved.

5. Restore FSX's legacy Windows components. Open Turn Windows features on or off and enable Legacy Components > DirectPlay if FSX requests it or it is missing. Run the official DirectX End-User Runtimes (June 2010) installer to restore the older side-by-side DirectX libraries; this does not replace the modern DirectX version built into Windows.

   Never download individual DLL files from an unofficial library. If Windows component installers fail or several older programmes are broken, run DISM /Online /Cleanup-Image /RestoreHealth followed by sfc /scannow from an elevated Windows Terminal, then restart.

6. Repair the correct FSX edition. For FSX: Steam Edition, use Steam's file-integrity verification and remember that it can replace modified default aircraft, scenery or gauge files. Do not apply the boxed FSX service packs to Steam Edition.

   For boxed FSX, run Setup from the original media and select Repair if offered. The recovery sequence is base FSX, then Service Pack 1, followed by either Service Pack 2 or Acceleration; Acceleration includes the later simulator updates. Back up customised files before either form of repair.

7. Test without start-up modules and complex add-ons. In the same AppData folder as FSX.cfg, temporarily rename dll.xml and exe.xml if they exist. Start a flight with a default aircraft at a default airport. If that works, restore modules, aircraft and scenery one at a time until the failure returns.

   This step matters because a Windows or security update may expose an old gauge or module fault even though the base simulator still works. A crash limited to one aircraft or airport is not a reason to reinstall all of FSX.

8. Clear unwanted compatibility settings. In fsx.exe properties, start with compatibility mode disabled. Test Run as administrator once as a diagnostic; if it fixes the problem, correct the relevant folder permissions instead of permanently running everything elevated. With Steam Edition, Steam and FSX should run at the same privilege level.

9. Roll back only the component that caused the failure. Roll back the graphics driver before removing an entire Windows update. Uninstall a Windows update only when the timing is exact, the earlier steps fail, and you have a restore point or backup. Reapply supported security updates after identifying and correcting the underlying driver, runtime or add-on problem.

Should I reinstall FSX after a Windows update?

Reinstall FSX only after configuration reset, driver repair and edition-specific file repair have failed. Reinstallation does not fix a broken graphics driver, missing Windows runtime or security quarantine, and with boxed FSX it can create another activation problem.

A clean reinstall is justified when default simulator files remain damaged after repair or Steam verification. Back up add-ons and personal files first, uninstall add-ons before the simulator where possible, restart Windows, and then reinstall only the correct edition and patch sequence.

What should I back up before the next Windows update?

Keep recoverable copies of the active FSX or FSX-SE AppData folder, saved flights under Documents, the active scenery configuration, add-on installers and any required licence information. Also record the graphics-driver package that works reliably with the simulator.

Copying only the main FSX installation folder is not a complete backup. FSX also relies on AppData, ProgramData, registry entries, SimConnect and legacy Windows components, so preserve the installers and configuration needed to rebuild those parts.