Requires that you own the GOG version of Fallout 4:
https://www.gog.com/game/fallout_4_game_of_the_year_edition

and that we're going to do a clean, from scratch and completely untouched installation of both Fallout 4 and Fallout: London. Meaning you'll have to make sure that there are no remnants of previous installation attempts still present on your machine.

We also won't be using the optional Galaxy client at any point, so if you have it up and running, shut it down.


Downloading the offline installers

1. While logged into the GOG website (https://www.gog.com) go into your library (https://www.gog.com/account)

2. Bring up the entry for Fallout 4: https://i.imgur.com/clarF4Z.jpeg

3. Click on it to expand: https://i.imgur.com/iTZOn9L.jpeg

4. Ignore the big blue "Download and Install Now", click on "Download Offline Backup Game Installers" instead to expand: https://i.imgur.com/mcLVsIq.jpeg

5. Ignore the installers for the "High Resolution Texture Pack" a little further down and download all 10 files ("Fallout 4: Game of the Year Edition (Part 1 of 10)" to "Fallout 4: Game of the Year Edition (Part 10 of 10)") to a folder somewhere on your drive: https://i.imgur.com/fSLigWo.jpeg (may have to change a certain visibility setting to have the .bin files show)

6. Make sure that all files have been downloaded correctly (check the file sizes) and are located in the same folder

7. Repeat the process for Fallout: London:
https://i.imgur.com/m35gCWh.jpeg
https://i.imgur.com/bzBeW5F.jpeg
https://i.imgur.com/iMOZGHx.jpeg


Installing Fallout 4 & Fallout: London

1. Navigate to the folder containing the 10 files for Fallout 4 (1x .exe & 9x .bin files) downloaded earlier - again make sure that all of them are present in the same folder and have been downloaded correctly

2. Double-click setup_fallout_4_game_of_the_year_edition_1.10.163.0_(64bit)_(66700).exe, and follow the install instructions

3. Once it's done installing, close the installation wizard

4. Repeat the the process for Fallout: London


Integrate Fallout: London into/Let Fallout: London take over Fallout 4

1. Navigate to the folder you have Fallout: London installed in and double-click installer.exe: https://i.imgur.com/gEqJrgq.jpeg

2. Follow the install instructions (it should automatically detect the location where you have Fallout 4 installed in, double-check if it's the correct path under "Fallout: London files will be installed in:", click "Change location", if necessary)

3. Once it's done installing/copying/integrating, close the installation wizard


Redundant since Buffout 4 already is and will be included with Fallout: London from v1.01 and onwards [̶b̶]̶I̶n̶s̶t̶a̶l̶l̶i̶n̶g̶ ̶B̶u̶f̶f̶o̶u̶t̶ ̶4̶ ̶&̶ ̶x̶S̶E̶ ̶P̶l̶u̶g̶i̶n̶ ̶P̶r̶e̶l̶o̶a̶d̶e̶r̶[̶/̶b̶]̶

̶A̶s̶ ̶d̶e̶s̶c̶r̶i̶b̶e̶d̶ ̶[̶u̶r̶l̶=̶"̶h̶t̶t̶p̶s̶:̶/̶/̶w̶w̶w̶.̶g̶o̶g̶.̶c̶o̶m̶/̶f̶o̶r̶u̶m̶/̶f̶a̶l̶l̶o̶u̶t̶_̶l̶o̶n̶d̶o̶n̶/̶f̶a̶l̶l̶o̶u̶t̶_ ̶l̶o̶n̶d̶o̶n̶_̶q̶u̶i̶c̶k̶_̶s̶t̶a̶r̶t̶_̶g̶u̶i̶d̶e̶_̶c̶o̶m̶m̶o̶n̶_̶b̶u̶g̶_̶f̶i̶x̶e̶s̶/̶p̶o̶s̶t̶1̶"̶]̶h̶e̶r̶e̶[̶/ ̶u̶r̶l̶]̶:̶

̶-̶ ̶M̶a̶n̶u̶a̶l̶l̶y̶ ̶d̶o̶w̶n̶l̶o̶a̶d̶ ̶[̶u̶r̶l̶=̶"̶h̶t̶t̶p̶s̶:̶/̶/̶w̶w̶w̶.̶n̶e̶x̶u̶s̶m̶o̶d̶s̶.̶c̶o̶m̶/̶f̶a̶l̶l̶o̶u̶t̶4̶/̶m̶o̶d̶s̶/̶3̶3̶9̶4̶6̶"̶]̶x̶S ̶E̶ ̶P̶l̶u̶g̶i̶n̶ ̶P̶r̶e̶l̶o̶a̶d̶e̶r̶[̶/̶u̶r̶l̶]̶
̶D̶r̶a̶g̶ ̶a̶n̶d̶ ̶d̶r̶o̶p̶ ̶t̶h̶e̶ ̶c̶o̶n̶t̶e̶n̶t̶s̶ ̶o̶f̶ ̶t̶h̶e̶ ̶d̶o̶w̶n̶l̶o̶a̶d̶e̶d̶ ̶z̶i̶p̶ ̶f̶o̶l̶d̶e̶r̶ ̶i̶n̶t̶o̶ ̶t̶h̶e̶ ̶[̶u̶]̶F̶a̶l̶l̶o̶u̶t̶ ̶4̶[̶/̶u̶]̶ ̶g̶a̶m̶e̶ ̶f̶o̶l̶d̶e̶r̶:̶
̶:̶\̶G̶O̶G̶\̶F̶a̶l̶l̶o̶u̶t̶ ̶4̶ ̶G̶O̶T̶Y̶

̶-̶ ̶M̶a̶n̶u̶a̶l̶l̶y̶ ̶d̶o̶w̶n̶l̶o̶a̶d̶ ̶[̶u̶r̶l̶=̶"̶h̶t̶t̶p̶s̶:̶/̶/̶w̶w̶w̶.̶n̶e̶x̶u̶s̶m̶o̶d̶s̶.̶c̶o̶m̶/̶f̶a̶l̶l̶o̶u̶t̶4̶/̶m̶o̶d̶s̶/̶4̶7̶3̶5̶9̶"̶]̶B̶u ̶f̶f̶o̶u̶t̶ ̶4̶[̶/̶u̶r̶l̶]̶
̶D̶r̶a̶g̶ ̶a̶n̶d̶ ̶d̶r̶o̶p̶ ̶t̶h̶e̶ ̶c̶o̶n̶t̶e̶n̶t̶s̶ ̶o̶f̶ ̶t̶h̶e̶ ̶d̶o̶w̶n̶l̶o̶a̶d̶e̶d̶ ̶z̶i̶p̶ ̶f̶o̶l̶d̶e̶r̶ ̶i̶n̶t̶o̶ ̶t̶h̶e̶ ̶[̶u̶]̶F̶a̶l̶l̶o̶u̶t̶ ̶4̶[̶/̶u̶]̶ ̶d̶a̶t̶a̶ ̶f̶o̶l̶d̶e̶r̶:̶
̶:̶\̶G̶O̶G̶\̶F̶a̶l̶l̶o̶u̶t̶ ̶4̶ ̶G̶O̶T̶Y̶\̶D̶a̶t̶a̶


Starting and running Fallout: London

1. Navigate to the folder you have Fallout 4 installed in and double-click f4se_loader.exe: https://i.imgur.com/H083m8u.jpeg

You may of course configure and reconfigure the graphical settings to your liking resp. what your machine allows for at any time via Fallout4Launcher.exe located in the Fallout 4 folder, just make sure you don't click "Play": https://i.imgur.com/DN2eqIN.jpeg
Always start and run Fallout: London by double-clicking f4se_loader.exe in the Fallout 4 folder.

And that's it - I'm currently at 12 hours into Fallout: London and only had 2 or 3 crashes.


Downloading and applying current and future updates

1. In your library bring up the entry for Fallout: London: https://i.imgur.com/XSHdnTz.jpeg

2. Download the offline installer for the patch/hotfix/update, in this case patch_fallout_london_2.31_Revision2_(75054)_to_V1.01_IV2.31R3_(75422).exe, for example, to the same folder where the offline installers for the base game are: https://i.imgur.com/RLC9HTC.jpeg

3. Again, make sure that the file(s) have been downloaded correctly (check the file size(s)) and, in case of multiple patch offline installers (1x .exe and several .bin files) that they are located in the same folder

4. Navigate to the above mentioned folder containing the patch offline installer(s) donwloaded earlier

5. Double-click patch_fallout_london_2.31_Revision2_(75054)_to_V1.01_IV2.31R3_(75422).exe (future patch offline installers will be named differently of course), and follow the install instructions

6. Once it's done installing, close the patch installation wizard

7. Navigate to the folder you have Fallout: London installed in and double-click installer.exe: https://i.imgur.com/gEqJrgq.jpeg

8. Click on Update and for the patched/updated version to be re-applied to the Fallout 4 installation, on Install: https://i.imgur.com/THOkmRq.jpeg
https://i.imgur.com/dpK2PL4.jpeg

9. Once it's done installing/copying/re-integrating, close the installation wizard

10. From the official patch notes: Navigate to your Fallout 4 Data folder: \GOG\Fallout 4 GOTY\Data and double-click on LondonWorldSpace - ClearUp.bat (this .bat is a simple script that will automatically delete any files that aren't needed anymore, this is required)

11. Navigate to the folder you have Fallout 4 installed in and double-click f4se_loader.exe: https://i.imgur.com/H083m8u.jpeg

12. Once a save is loaded up, an in-game text message ("Fallout: London Updated to v1.01") should appear, further confirming that the patch/hotfix/update has been applied successfully: https://i.imgur.com/NbqQ1Vk.jpeg


Since all the settings (except for the key bindings) have been reset you will have to reconfigure the graphical settings to your liking resp. what your machine allows for via Fallout4Launcher.exe located in the Fallout 4 folder, just, again, make sure you don't click "Play": https://i.imgur.com/DN2eqIN.jpeg
and start and run Fallout: London by double-clicking f4se_loader.exe in the Fallout 4 folder.

More or less exactly in the order I did it too.

No installing or running the game through Galaxy or other third party mod managers - which only add to the list of potential causes for all sorts of issues making it even harder to track down and trouble-shoot - and using the GOG backup offline installers for both Fallout 4 and Fallout: London.

Slap Buffout 4 on top of it and job's a good 'un. Nothing but smooth sailing from here on. With the occasional crash now and then, but that's down to the Creation Engine doing what it does.

Your mileage may still vary of course, mainly depending on your setup, system's specs and about a million other little things potentially factoring in.

It may be an improvement for you, but I don't really consider "2 or 3 crashes" to be "stable and flawlessly".

There needs to be a patch dealing with the crashes, until then I don't really consider it playable. I get that it's a free mod so I'm not complaining, just saying it isn't really worth jumping through all the hoops to get the installation right only to find that it still crashes, just not as much.

Considering that we're talking about the Creation Engine here "2 or 3 crashes" over the span of 12 hours can be considered "stable and flawlessly".

Patch is needed.
While the game is somehow playable, it ticks me off, when there is a crash unexpectedly.
While autosave is fine, every 5 minutes while in pip boy, also at sleeping and such... I still hope that these crashes will be resolved properly.

Especially later into the game, mostly enemies get a lot more challenging, and defeating them is also question of luck, so when I get a crash right after such battle, it is not a simple question of redoing it again, it is a real pain getting the same results.

EDIT: also some dialogues seems to be broken <attached>

.. well, attachment didn't work, so here is imgur>
https://imgur.com/HFa0z1L

It's playable for some folks, for others it's completely unplayable. There are patches coming, but there's a lot of work that needs to be done, I literally can't even get past that initial train because it crashes before the station loads and I don't have the necessary weapons or gear to just jump off the bridge and go around that way.

For some and probably many, uninstalling F4 is a deal-breaker.

The train crash crash (the train crashes, and also the game crashes) is dealt with Baffout 4, just for people with systems that are upper case sensitive, make sure that the manual installation of Buffout 4 matches, including subdirs.
i.e. Plugins vs plungs

and of course, xSE must be installed first (before Buffout 4)

And yeah, if one cannot get through the train crash, it is a definition of unplayable, which is worse than my state of the game. isn't it just Steam specific problem? As for GoG you can use the offline installer and basically make as many copies as you wish, each with different setup (vanilla, mod A, mod B...)

I originally had F4 on steam and had real issues to keep the .ini file intact (in order to have frame rate cap unlocked), as steam always auto-rewrote these files (and after installing mods, it just deactivated achievs, meh)

But GoG should be pristine in the question of having unlimited variations of your fav game.

But I might be also mistaken and in windows this does not work (under Linux, I can have limitless iterations of any game, without any hardship, so no uninstall needed at all)

For the tiny few that have more then one game computer otherwise no you cant.

If this doesn't work I will find you and leave a half eaten twinkie in your mail box

nice guide!

some extra mods that smoothed out frequent crashing for me:

(make sure you get the correct downloads for version 1.10.163.0)

- Weapon Debris Crash Fix by Antonix35 : https://www.nexusmods.com/fallout4/mods/48078
- High FPS Physics Fix by Antonix35 : https://www.nexusmods.com/fallout4/mods/44798
- Sprint Stuttering Fix by Antonix35 : https://www.nexusmods.com/fallout4/mods/47760
- Long Loading Times Fix by Antonix35 : https://www.nexusmods.com/fallout4/mods/73469

(be sure to copy them to the correct "Fallout 4 GOTY/Data/F4SE" subfolder, not the "Fallout London" folder)

Outcomes:
- fixed very long load times (now it's max 7 seconds)
- solved frequent random crashes (was around every 7 mins)

The attached image shows the result.

After extra 20 hours of gameplay, these four (or one/some of those) brought desired results.
While still not 100% flawless, the period between opening the game and a crash (drop to OS) is now 2 or more hours, which is acceptable (even vanilla F4 does this)

The remaining concern is only with the mod itself, specifically some quests are broken, but nothing that wouldn't fix:
SQT
SQS
setstage
desptie it also entails some good guessing on the setstage (as not all quests are linear), but game is well playable

Thank you.

Worked out great and on first try, thanks for the step-by-step.
Didn't even apply Buffout4 yet but still got past the infamous train crash... crash, also on first try.

Thanks, following this guide was the only way i was able to start playing the game. :)

Downloading and applying current and future updates

1. In your library bring up the entry for Fallout: London: https://i.imgur.com/XSHdnTz.jpeg

2. Download the offline installer for the patch/hotfix/update, in this case patch_fallout_london_2.31_Revision2_(75054)_to_V1.01_IV2.31R3_(75422).exe, for example, to the same folder where the offline installers for the base game are: https://i.imgur.com/RLC9HTC.jpeg

3. Again, make sure that the file(s) have been downloaded correctly (check the file size(s)) and, in case of multiple patch offline installers (1x .exe and several .bin files) that they are located in the same folder

4. Navigate to the above mentioned folder containing the patch offline installer(s) donwloaded earlier

5. Double-click patch_fallout_london_2.31_Revision2_(75054)_to_V1.01_IV2.31R3_(75422).exe (future patch offline installers will be named differently of course), and follow the install instructions

6. Once it's done installing, close the patch installation wizard

7. Navigate to the folder you have Fallout: London installed in and double-click installer.exe: https://i.imgur.com/gEqJrgq.jpeg

8. Click on Update and for the patched/updated version to be re-applied to the Fallout 4 installation, on Install: https://i.imgur.com/THOkmRq.jpeg
https://i.imgur.com/dpK2PL4.jpeg

9. Once it's done installing/copying/re-integrating, close the installation wizard

10. From the official patch notes: Navigate to your Fallout 4 Data folder: \GOG\Fallout 4 GOTY\Data and double-click on LondonWorldSpace - ClearUp.bat (this .bat is a simple script that will automatically delete any files that aren't needed anymore, this is required)

11. Navigate to the folder you have Fallout 4 installed in and double-click f4se_loader.exe: https://i.imgur.com/H083m8u.jpeg

12. Once a save is loaded up, an in-game text message ("Fallout: London Updated to v1.01") should appear, further confirming that the patch/hotfix/update has been applied successfully: https://i.imgur.com/NbqQ1Vk.jpeg


Since all the settings (except for the key bindings) have been reset you will have to reconfigure the graphical settings to your liking resp. what your machine allows for via Fallout4Launcher.exe located in the Fallout 4 folder, just, again, make sure you don't click "Play": https://i.imgur.com/DN2eqIN.jpeg
and start and run Fallout: London by double-clicking f4se_loader.exe in the Fallout 4 folder.