FSX Acceleration must install in the same folder and drive as boxed FSX. Learn how to use drive D: or G: and avoid Steam Edition errors.
No. Boxed FSX Acceleration cannot be installed as a separate product on another drive; it must update the registered Microsoft Flight Simulator X folder containing fsx.exe. FSX itself may be installed on D:, G: or another fixed drive, but move or reinstall the complete boxed simulator there before adding Acceleration.
Why must Acceleration use the same drive as FSX?
Acceleration is an expansion for boxed Microsoft Flight Simulator X, not a standalone simulator. Its installer adds and replaces files throughout the existing FSX installation, including core components, aircraft, gauges, effects, scenery and missions.
The installer finds boxed FSX through its registered installation path. If it displays a destination, that destination must be the existing root folder containing fsx.exe, not an empty folder created on another drive. If you are unsure which directory is the root, use these ways to locate the actual FSX installation folder.
FSX Gold Edition follows the same rule. Its Acceleration component expands the base simulator supplied in the package; it does not create a second installation.
Can I install FSX Acceleration on drive D: or disk G:?
You can use drive D:, G: or another fixed drive only when boxed FSX itself is already installed and registered there. The drive letter is irrelevant; the base simulator and Acceleration must share the same FSX root folder.
If a Polish Windows installation labels the volume Dysk (G:), that simply means drive G:. Install boxed FSX to that drive first, run it successfully, and then let the Acceleration installer detect the same location.
| Existing installation | Can Acceleration use the requested drive? | Correct action |
|---|---|---|
| Boxed FSX is on C:, but Acceleration is to go on G: | No | Move or reinstall the complete FSX installation on G: first. |
| Boxed FSX is already installed on G: | Yes | Let Acceleration install into the registered FSX folder on G:. |
| FSX Gold Edition is installed on D: | Yes | Install its Acceleration component into that same FSX installation. |
| FSX: Steam Edition is installed | No boxed installer is needed | Do not install the boxed Acceleration expansion over Steam Edition. |
A fixed internal SSD or hard drive is preferable to removable storage. A disconnected device or changed drive letter will break FSX paths, scenery registrations and add-on installers.
How do I move FSX before installing Acceleration?
Reinstalling boxed FSX on the intended drive is usually the cleanest option because copying its folder does not update the Windows registry, uninstall records or paths saved by add-ons. An established installation can sometimes be migrated, but follow our safe boxed-FSX relocation options rather than dragging the folder in File Explorer.
- Confirm which FSX edition you have. These steps apply to boxed FSX and the Acceleration expansion, not FSX: Steam Edition.
- Back up customised content. Preserve add-on installers, aircraft, scenery, liveries, saved flights and any configuration files you deliberately changed. FSX stores user data outside its main installation folder as well, so copying only that folder is not a complete backup.
- Remove Acceleration first. If it is already installed or a previous attempt left it listed among Windows' installed applications, uninstall it before removing the base simulator.
- Install boxed FSX on the new drive. Choose a fixed-drive path such as
D:\FSXorG:\FSX. A simple custom path can also reduce permission trouble with older add-on installers. - Run the base simulator once. Complete its normal setup or activation, reach the main menu, close FSX and allow Windows to save the registered path.
- Install Acceleration. Let setup use the boxed FSX location it detects. Do not redirect it to an empty folder or a copied Steam Edition directory.
- Test before restoring add-ons. Start FSX and verify the clean installation works before reinstalling aircraft, scenery and utilities one group at a time.
What if Acceleration cannot find FSX after a drive change?
If Acceleration cannot find FSX after it was moved, the registered installation path is usually missing, stale or pointing to the old drive. The presence of fsx.exe alone does not prove that Windows recognises the copied folder as an installed boxed edition.
- Check that you are targeting boxed FSX rather than FSX: Steam Edition.
- Verify that the registered root is the folder containing
fsx.exe, not an aircraft, add-on or empty destination folder. - If FSX was copied manually, reinstall it or complete a proper migration instead of guessing or downloading replacement registry entries.
- Remove an incomplete Acceleration installation through Windows before running setup again.
- If setup reports an access or disc-reading problem rather than a missing simulator, address that error separately; changing the destination drive will not fix it.
For detection failures, permissions problems and incomplete installations, follow our specific fixes for FSX Acceleration setup errors.
Does this apply to FSX: Steam Edition?
Do not install the boxed Acceleration expansion over FSX: Steam Edition on any drive. Steam Edition already includes the Acceleration content and functionality, while the boxed installer expects a registered boxed FSX installation.
If boxed FSX and Steam Edition are both installed, keep them in separate folders. Older installers can confuse the two editions, but Acceleration must target only the registered boxed copy; our guide explains what Steam Edition already includes from Acceleration.
Can FSX add-ons go on another drive even when Acceleration cannot?
Some large add-ons can use another drive even though Acceleration cannot. Mesh, photoreal scenery and other scenery folders may be stored elsewhere and registered through the FSX Scenery Library when the add-on supports that arrangement.
Aircraft, gauges, effects and modules usually rely on specific locations within the FSX directory. NTFS junctions or symbolic links can redirect folders, but we do not recommend using them to split Acceleration across drives: its installer and uninstaller expect the registered FSX installation tree to remain intact.