How to Install Fallout London: A Complete Setup Guide

Fallout London is one of the most ambitious mod projects ever released for Fallout 4 — a full conversion mod that moves the story entirely to a post-apocalyptic version of England's capital. It's not a small patch you drop into a folder. It's effectively a standalone game built on Fallout 4's engine, and installing it correctly requires a few careful steps that differ significantly from typical mod installs.

What Fallout London Actually Is

Before diving into installation, it helps to understand what you're working with. Fallout London is a total conversion mod, meaning it replaces or overrides most of the base game's content rather than simply adding to it. The mod was developed by Team FOLON and released through GOG (Good Old Games) as a free, standalone download for owners of Fallout 4 on PC.

Because it's a total conversion, it requires a specific version of Fallout 4 — and this is where most installation problems begin.

The Version Problem: Why This Step Is Critical 🎮

When Bethesda released the next-gen update for Fallout 4 in April 2024, it bumped the game to a new engine version. Fallout London was built and tested against the pre-next-gen version of the game. Running it on the updated version can cause crashes, missing content, or failed launches.

You need to downgrade Fallout 4 to version 1.10.163 (the last pre-next-gen build) before installing the mod. This is not optional — it's the single most important compatibility requirement.

How to downgrade on Steam:

1. Open Steam and go to your Library
2. Right-click Fallout 4 → Properties
3. Go to the Betas tab
4. From the dropdown, select steam_legacy - Pre-next gen update
5. Steam will download the older version automatically

Once downgraded, disable automatic updates for Fallout 4 in Steam by setting the update option to "Only update this game when I launch it" — and then always launch through your mod manager, not Steam directly.

Installing via GOG: The Recommended Method

The cleanest installation path for Fallout London is through GOG Galaxy or a direct GOG download:

1. Create a free GOG account if you don't have one
2. Link your Steam account to GOG to verify Fallout 4 ownership
3. Download the Fallout London installer from your GOG library
4. Run the installer and point it to a clean, separate directory — not inside your existing Fallout 4 folder
5. Launch through the provided executable or GOG Galaxy

This method bundles most dependencies and reduces the manual setup required compared to manual mod manager installs.

Manual Installation via Mod Manager

Some players prefer using Mod Organizer 2 (MO2) or Vortex, which gives more control over load order and conflict resolution. This path is more involved:

• Start with a clean Fallout 4 install (downgraded to 1.10.163)
• Install the Fallout 4 Script Extender (F4SE) — required for many of Fallout London's systems to function
• Download the Fallout London files from GOG or the mod's official release page
• Load the mod through your manager, ensuring it sits at the correct position in your load order
• Confirm all required master files are active

MO2 is generally considered more stable for large mod setups because it uses a virtual file system that doesn't overwrite your base game files.

System Requirements and Performance Variables

Fallout London is a large, complex mod and performance depends heavily on your hardware. General benchmarks to keep in mind:

Loading times, NPC density, and open-world traversal are all affected by storage speed. Players on HDDs often report noticeably longer load screens compared to those on SSDs.

Common Installation Issues

Crash on startup: Almost always a version mismatch. Confirm you're on 1.10.163, not the next-gen build.

Missing textures or black screens: Usually indicates F4SE isn't running correctly, or the mod files weren't fully extracted.

Mod manager conflicts: If you have existing Fallout 4 mods installed, they can conflict with Fallout London's assets. A clean, dedicated install is strongly recommended.

GOG verification failure: Occasionally GOG has difficulty linking Steam accounts. Clearing GOG Galaxy's cache or relinking through a browser session usually resolves it.

What Affects Your Specific Experience

Installation complexity varies depending on several personal factors:

• Whether you already own a modded or vanilla install of Fallout 4
• Whether you're comfortable using mod managers vs. direct installs
• Your hardware and whether you'll need to adjust in-game settings for stable performance
• Whether you want to run additional mods alongside Fallout London (which adds significant complexity)

Players starting from a fresh, unmodded Fallout 4 install generally have the smoothest time. Those with existing mod setups need to think carefully about whether to run a separate instance of the game dedicated to Fallout London.

The official Team FOLON Discord and wiki remain the most current resources for troubleshooting, since compatibility notes are updated as patches are released. Your own setup — hardware, existing mods, platform version — is ultimately what determines which steps you'll need to take and how much friction you'll encounter along the way.