Install: MSFS

Experimental

MSFS support has not yet been integration-tested against the simulator. This procedure documents the intended flow, but expect rough edges — and please report what you find.

On MSFS the E3X runs as an external SimConnect client: the sim starts the E3X, the E3X opens its display window, and when the sim exits — quit or crash — the E3X notices within about 15 seconds and closes with it.

Two prerequisites:

• SimConnect.dll. Microsoft’s SDK library is not bundled with the E3X. It’s found automatically from an installed MSFS SDK or the sim’s own folders; g3x-core doctor prints which copy was found, or every place it looked. Without it the MSFS source can’t start.
• An auto-start entry in exe.xml, the same documented hook FSUIPC and MobiFlight use.

The recommended way: g3x-core install msfs

With the sim fully exited, run from the E3X install folder:

g3x-core install msfs

It finds exe.xml for MSFS 2020 and 2024 (Store and Steam), backs the file up with a timestamp, and adds one Launch.Addon block named “Emrelia E3X” — parsing and re-writing the XML properly, keeping every other add-on’s block intact. Re-running it is safe; it maintains exactly one block. It refuses to run while the sim is open. g3x-core uninstall msfs removes the block again.

The rest of this page documents what that command writes, for when you want to edit the file yourself or check what’s there — exe.xml is shared by every auto-starting add-on, and a corrupted file silently stops all of them, so the manual procedure below is a block you can read before you paste it.

Caution

Edit exe.xml only with the sim fully exited — not minimized, not at the main menu. MSFS rewrites the file on shutdown and will discard your edit otherwise.

1. Find exe.xml

The reliable rule: exe.xml sits in the same folder as UserCfg.opt.

Sim	Store	Folder
MSFS 2020	MS Store / Game Pass	%LOCALAPPDATA%\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalCache\
MSFS 2020	Steam	%APPDATA%\Microsoft Flight Simulator\
MSFS 2024	MS Store / Game Pass	%LOCALAPPDATA%\Packages\Microsoft.Limitless_8wekyb3d8bbwe\LocalCache\
MSFS 2024	Steam	%APPDATA%\Microsoft Flight Simulator 2024\

If the file doesn’t exist, the sim has simply never had an auto-start add-on; you’ll create it below.

Back it up first:

copy exe.xml exe.xml.bak

2. Add the launch block

Add one <Launch.Addon> element inside the existing <SimBase.Document>, alongside any blocks already there. A complete file with nothing else installed looks like this (adjust the path to where you installed the E3X):

<?xml version="1.0" encoding="Windows-1252"?>
<SimBase.Document Type="Launch" version="1,0">
    <Descr>Launch</Descr>
    <Filename>exe.xml</Filename>
    <Disabled>False</Disabled>
    <Launch.ManualLoad>False</Launch.ManualLoad>
    <Launch.Addon>
        <Disabled>False</Disabled>
        <ManualLoad>False</ManualLoad>
        <Name>Emrelia E3X</Name>
        <Path>C:\Users\you\AppData\Local\Programs\EmreliaE3X\core\g3x-corew.exe</Path>
        <CommandLine>--source msfs --supervised simconnect --open-browser</CommandLine>
    </Launch.Addon>
</SimBase.Document>

If other add-ons are already in the file, copy only the <Launch.Addon> element and paste it immediately before the closing </SimBase.Document>.

3. Check it before you fly

Does the XML still parse? MSFS won’t tell you if it doesn’t. In PowerShell:

[xml](Get-Content -Raw "$env:APPDATA\Microsoft Flight Simulator 2024\exe.xml")

An echoed document means well-formed; a red conversion error means broken — restore your backup and try again.

Start the sim. The E3X window appears within a few seconds of the sim reaching the main menu — before you pick an aircraft — and shows an unpopulated display until a flight is loaded. That’s the intended shape. Quit the sim; the window closes on its own within ~15 seconds.

Optional flags

• --real-weather — MSFS can’t report its live-weather mode, so real-world METAR/radar feeds need this flag.
• --no-terrain-fetch — disable the background terrain tile fetcher.

If exe.xml breaks

A malformed exe.xml silently stops every auto-start add-on. With the sim closed:

1. Restore the backup: copy exe.xml.bak exe.xml
2. No backup? Delete exe.xml — the sim recreates a valid one (you’ll need to re-add other add-ons’ blocks too).

Uninstall

Close the sim, then delete the <Launch.Addon> block — or set <Disabled>True</Disabled>, which turns it off without the risk of editing.