For some time now, we’ve been posting some pretty spiffy mods for Fallout 3 (All thanks to the modding community, of course). But until now.. It hasn’t dawned on me that we’ve been posting all these mods, without even telling you guys how to install them in the first place! Well, today will be the day we fix that problem. I’ll tell you all you need to know to install the hottest mods.

There is really only 2 different steps/ways to installing Fallout 3 mods (Not including the first step below, since you’ll only need to do it once). One is by copy and pasting lines of text in your “ArchiveInvalidation” folder, and the other is putting files into your “Data” folder. Doesn’t sound to hard, does it? *Watches you nod up and down* Good, then lets begin.

Lets start off by finding your Fallout 3 program folder, in that folder, find the file called “Fallout_default“. By default, it should be located at C:\Program Files\Bethesda Softworks\Fallout3\

In this document, locate the text line bInvalidateOlderFiles=0.  Now change the “0” into a “1”, then save and exit.

If you cannot change it manually, then download this Fallout_Default.ini file here (This file has the binvalidateolderfiles = 1).  Once it is downloaded, copy and paste the file over your original Fallout_Default.ini file in your programs folder.


Now locate a text file called “ArchiveInvalidation” if you don’t have one, then go ahead and make one (easiest way is making it as a notepad).  Some mods need you to copy and paste certain text into this to make the mod work.  For Example:

“3 Suns” mod by Nopheros, requires you to copy and paste:


Into the “ArchiveInvalidation” text file (Order at which you paste things, do not matter).  Generally, if something needs to be pasted into the text file, they will have a read me/text file inside the archive of a mod stating what to do.


Another type of mod, that mod creators use are “.esp” files.  Probably the most easiest to install.  Simply look into your Fallout 3 folder, and find the “Data” folder.  If you do not have one, then simply make a new folder called “Data”.  In this folder is where you will put all the .esp files (Along with other sounds/texture/mesh/etc mods.. But we’ll talk more about this in the next step).  For example:

“BasicNeeds” mod by AnT01, requires you to simply put the .esp file into the “Data” folder, and just like that the mod is installed (Though keep in mind some mods require additional steps).

The only way you can activate them, is by using the “FalloutLauncher” instead of the regular Fallout3.exe.  When you open the launcher, you’ll see a pretty straight forward menu.  In this menu, click “Data files”  and that will pop up another menu that consists of all the .esp mods you have in your “Data” folder.  Simply check the ones you want to use, and when you start the game, the mods will be working (Note that you may have to do this every time you start-up the game).


Now for the last kind of mods you’ll come across (generally).  Usually this step in mods are used by the ones that effect in-game <code>textures/sounds/meshes/shades/menu/music/etc</code>.  If the mod contains a folder that is named “Data” then simply merge it with your current “Data folder” in the Fallout 3 Programs folder.  If the folder isn’t named “Data” and instead called “Textures” or “meshes” (etc) then just put the whole folder inside your data folder and merge.  For example:

“Sungo Vault Girl” mod by Sungo, requires you to merge the mod’s “data” folder with your “data” folder in the Fallout 3 program “folder” (That’s alot of folders!  Anyways, it also requires you to copy and paste some text into your “ArchiveInvalidation” text file also).


There you have it, those are generally the only mods you will come across.  But like I said before, not all mods will use the same process of steps.  Some might only need to use a simple .esp file into the data folder, while others may need to be merged with your data folder, along with adding a .esp file, and the requirement of copy and pasting something in your “ArchiveInvalidation” text file.

Hopefully this helps you install all the mods you want with minimum confusion.  Please feel free to comment, and leave questions if you are confused about something.   I’ll be glad to help you out.

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