The_Sagemaster: I've tried that, downloaded the 3 parts for the offline installer for Fallout 3. That didn't work. I even uninstalled the original game and reinstalled it using the offline installer, and still when I opened it up I got the pop-up that "the app may not work correctly" Same issue, opening up the game and starting a new game causes it to crash. Is this a settings things for my computer?

The_Sagemaster: I've tried that, downloaded the 3 parts for the offline installer for Fallout 3. That didn't work. I even uninstalled the original game and reinstalled it using the offline installer, and still when I opened it up I got the pop-up that "the app may not work correctly" Same issue, opening up the game and starting a new game causes it to crash. Is this a settings things for my computer?

The_Sagemaster: I've tried that, downloaded the 3 parts for the offline installer for Fallout 3. That didn't work. I even uninstalled the original game and reinstalled it using the offline installer, and still when I opened it up I got the pop-up that "the app may not work correctly" Same issue, opening up the game and starting a new game causes it to crash. Is this a settings things for my computer?

reallynonessential: I'm not sure if you've checked the properties of the .EXE, sometimes there's a "unknown source" type of automatic blocking Windows does, and there's a simple fix for that. Two things to check: 1) if you right-click to look at the properties of the game file Fallout3.exe, does it need to be unblocked? or 2) in file properties does it work if you set the compatibility to an earlier version of Windows? In case you're unfamiliar here's a good set of instructions: https://www.elevenforum.com/t/enable-or-disable-run-app-in-compatibility-mode-in-windows-11.6608/
By the way, users must go through the right-click menu for compatibility mode options to show in some versions of Win 11.

This really does sound like it might be a problem with d3d9 support in Windows 11, or possib ly due to default behavior of Windows Defender or Windows security features like ASLR. I'm hoping someone has found out whether it is one of those types of problems and can add a solution here.

Try adding the game executable Fallout3.exe as an exception under Data Execution Prevention, and if that doesn't work also add it as an exception for Exploit protection (you'll have to add the exact file path to the Fallout3.exe - open Windows Defender Security Center and click on App & browser control and there should be a link to Exploit protection settings).

AndLes77: Using an AMD GPU I had to download the customized d3d9.dll (NexusMod -> 17209). Placed it within the Fallout folder.

The_Sagemaster: I tried that and so far it hasn't worked. I firstly tried the right-click on the game file, and it didn't look like anything needed to be unblocked. I did try to change the compatibility, but that didn't do anything. The only ones available to me to change it were to a Windows 7, 8, 95, or Vista, all of which are older versions of Windows. The game still crashed.

I did try to change the game's details under Data Execution Prevention. I went to the Exploit Protection and added the file for Fallout3.exe, then went down to Date Execution Prevention, clicked the box that said "Override Systems Settings" and turned it to "Off," Still didn't do anything. Granted, I'm not a tech wizard so I might have goofed up on some of this stuff.

agnaf: This was my solution - I tried hours getting the game to work. It was easy and quick. No crazy stuff. You have to put the fallout.ini in the Fallout Foulder (users > documents > Games), the dll needs to be in the same foulder as your fallout.exe is.

Just download this mod: https://www.nexusmods.com/fallout3/mods/17209

The_Sagemaster: I just downloaded Fallout 3 Game of the Year Edition through GOG through the whole Amazon Prime Gaming free code thing. Anyways, I installed GOG Galaxy, got Fallout 3, downloaded it onto my computer, but it doesn't run.

Here's the details: My computer is Lenovo Windows 11 Home Edition, 23H2 Version, Intel(R) Core(TM) i3-10110U CPU @ 2.10GHz 2.59 GHz.

I have all the game files and can hit "play" on GOG Galaxy. This opens up the tab, with "Play" "Options" "Data Files" and all that. But I also get this message that instantly pops up as well, which says that "this app may not work correctly" because it "causes security or performance issues on Windows" If I click "Learn More" it tries to download a file entitled gfwlivesetup.exe. However, I get hit with another pop-up which says that the install of "Games for Windows Marketplace" failed, that "a network error occurred while attempting to get information from the server. Check your network connection and retry." It offers looking at the log files, which say the exact same thing, or clicking on support, which takes me to the Xbox page on Microsoft.

I can still hit play in the original Fallout 3 screen, and that starts the game, bringing me to the loading screen. I can click all the other buttons, but if I click "New" and "Start a new game --> Yes" then it just crashes and shuts down.

So I guess I'm just wondering what I need to do in order to run Fallout 3 on my computer. I just got it because of the free deal offered through Amazon Prime Gaming, and it looks like it runs all fine until I click a new campaign. I'm not sure why my computer can't download the Games of Windows Marketplace or what the security issues is. Does this have something to do with my computer being a Windows 11 (I updated it last year, I think)?

I'm not a very tech-savvy person in regards to computer and game files, so I would greatly appreciate some advice and clarity on what do in this situation. If somebody could help I would be greatly appreciative!

(I've included some screenshots of the pop-ups)