Reinstall FSX safely: back up settings and add-ons, restore them in the right order, and stop old files from breaking the clean installation.
To reinstall FSX or FSX: Steam Edition safely, back up the user-data folders, the complete simulator folder and any external scenery before uninstalling. Reinstall the same edition and updates, launch the clean simulator once, then reinstall add-ons with their original installers and restore settings selectively rather than copying the entire old installation over the new one.
What should I back up before reinstalling FSX?
Back up every location FSX uses, not just the main installation folder. Our folder-by-folder FSX backup checklist covers the files in detail, but these are the essential groups:
| Data | Typical location | How to preserve it |
|---|---|---|
| Aircraft, gauges, effects and modules | The active FSX installation folder, including SimObjects, Gauges, Effects, Sound and Modules | Archive the complete folder as a safety copy, but do not later paste it wholesale over the new installation. |
| Personal configuration | %APPDATA%\Microsoft\FSX or %APPDATA%\Microsoft\FSX-SE | Keep FSX.cfg, control profiles, dll.xml and exe.xml for selective restoration. |
| Scenery configuration | %PROGRAMDATA%\Microsoft\FSX or the corresponding FSX-SE folder | Preserve scenery.cfg, especially if the scenery library has many manually arranged layers. |
| Flights and logbook | Documents\Flight Simulator X Files or the Steam Edition equivalent | Copy the whole folder so saved flights, flight plans and logbook data are retained. |
| External add-ons | Any scenery, aircraft library or utility folder outside FSX | Copy the folders and record their full paths. Also retain installers, licence details and configuration files. |
FSX: Steam Edition can use either FSX or FSX-SE folder names, depending on whether boxed FSX has existed under that Windows account. Back up both when present; the active configuration normally has the most recently modified FSX.cfg.
Keep the backup on another drive if possible. Steam file verification, cloud features and an uninstaller's offer to retain personal data are not substitutes for a separate copy.
How do I reinstall FSX safely?
The safest method separates the old installation from the new one and proves that clean FSX works before any old content returns.
- Record what is installed. Note whether you use boxed FSX, Acceleration or FSX: Steam Edition, along with the installation path, scenery order and add-on versions. Retain original installers and licence information.
- Close FSX and make the backup. Verify that several files can actually be opened from the backup rather than assuming the copy completed correctly.
- Deactivate protected add-ons where supported. Some commercial products provide a licence-return or deactivation function. Use it before removing anything, because copying their files rarely preserves activation.
- Uninstall add-ons before FSX. Installer-based aircraft, scenery and utilities may need the simulator's registry entries to remove themselves correctly. After that, uninstall FSX through Windows or Steam; follow our safe order for removing FSX and its remaining files if the goal is a genuinely clean installation.
- Isolate anything left behind. Rename residual installation and configuration folders with an
-oldsuffix instead of immediately deleting them. This prevents the new installation from silently reusing damaged files while leaving an emergency recovery copy. - Reinstall the correct edition. Boxed FSX should be installed from its media and brought to the same final service-pack or Acceleration level before add-ons are added. Steam Edition should be installed through the selected Steam library and allowed to finish updating. Do not place boxed FSX executables or core DLLs into Steam Edition.
- Run a clean baseline test. Start FSX using the same Windows account that will normally run it, load a default aircraft at a default airport, check the controls and close the simulator normally. This creates fresh configuration files.
- Reinstall add-ons in small groups. Use original installers for modules, complex aircraft and products with shared components. Install required dependencies first, broad scenery before local airports, and test FSX after each manageable batch.
- Restore personal data selectively. Bring back saved flights, the logbook and known-good control profiles first. Restore or rebuild configuration files only after the relevant add-ons have been installed.
Should I verify Steam files instead of reinstalling?
Steam file verification is the better first choice when only a default FSX file is missing or damaged. It can replace altered stock files, but it does not reset the configuration under %APPDATA%, remove unwanted third-party files or repair an add-on's external components.
Back up first because verification can overwrite stock files modified by older add-ons. If the fault survives verification or the installation contains unknown leftovers, a separated clean reinstall gives a more reliable result.
Can I copy the old FSX folder back?
Do not copy the entire old FSX folder over the clean installation, because that restores the same damaged files, obsolete modules and conflicting default-file replacements that the reinstall was meant to remove.
- Self-contained freeware aircraft can usually be copied individually once any documented gauges, effects or sounds are also restored.
- External scenery folders may remain where they are, but they must be registered again unless a compatible
scenery.cfgis restored. - Complex aircraft and utilities should be reinstalled. Their files may be spread across FSX, Windows user-data folders and shared component locations.
- Modified stock files should remain out of the installation until the responsible add-on has been tested and confirmed compatible.
A mistake we see constantly is treating the old simulator folder as a ready-made backup image. It is valuable for recovering individual content, not as a replacement for proper add-on installation.
Which FSX settings should I restore?
Restore personal files freely, path-dependent files carefully and executable-loading files only after their add-ons are present.
| File or setting | Recommended treatment |
|---|---|
| Saved flights, flight plans and logbook | Copy them back after the clean simulator has created its Documents folder. |
| Control profiles | Restore after testing the controls once. If Windows has assigned different device identifiers, rebuild the affected bindings rather than forcing a broken profile. |
scenery.cfg | Restore only when every scenery path is still valid. Otherwise, register the scenery again and recreate the layer order. |
FSX.cfg | Keep the fresh file when the cause of the old problem is unknown. Reapply settings through FSX, or test the old file only after making a copy of the new one. |
dll.xml and exe.xml | Restore entries only after their modules have been reinstalled. Stale paths commonly cause start-up errors, missing menus and background programs that fail to launch. |
What changes if FSX is going to another drive or edition?
A changed drive letter or edition turns the reinstall into a migration because saved paths and installer detection may no longer match.
For another drive, boxed FSX should be reinstalled to the intended location, while Steam Edition should be managed through Steam's storage tools. Our procedure for moving FSX and external add-ons between drives explains how to handle scenery paths and avoid dragging an incomplete installation.
Moving from boxed FSX to Steam Edition also requires compatibility checks. Many aircraft and scenery packages work, but installers, gauges, modules and activation systems may expect a particular edition or registry path; use our guide to add-ons that can be transferred to Steam Edition before copying anything.
What if the original fault returns after reinstalling?
The stage at which the fault returns usually identifies what reintroduced it.
- If FSX fails before any settings or add-ons are restored, investigate the base installation, Windows permissions, required components or hardware drivers.
- If it fails immediately after restoring FSX.cfg, keep the newly generated file and rebuild the settings.
- If the problem appears after an add-on batch, remove or disable that batch and reinstall its contents one at a time.
- If it returns after copying the whole old simulator folder, isolate that folder again and repeat the clean baseline test; the reinstall was effectively overwritten.
Do not delete the backup until FSX has started, loaded and closed correctly through several add-on restoration stages. Once everything is stable, retain the personal data and installers even if the temporary copy of the old simulator folder is no longer needed.