Although I don't have Fallout4, after some research I believe these games set some strange screen resolutions for a while and that will makes full-screen unity games crash. I will try to find a solution but I'm not sure if it can be solved.
Try to set the game's screen mode to "Borderless Window Full-screen" if the game supports. That might be able to solve this problem.

Oh, and it may be caused by Fallout4 have just cost all your VRAM and there are no enough VRAM for our program. If so, I think there is no other way than just pause or close this wallpaper before you open those games. It should be closed since you won't be able to see the wallpaper when you play games, after all.

For the 1rt solution : windowed without bordeless don't work , the same problem and windowed i don't play ^^
And yes when i play i don't need to see your great wallpaper =)

The bug don't exist with other games , maybe mod on fallout do that ( bad optimisation or i got an ENB , maybe that the problem ) Actually i have try with fallout 4 , guild wars 2 , RWBY and overwatch and only fallout do that .

You don't need to focus on this problem =)
Actually i just wait sound on your program when i clic =)

and just a another question , when we got full pictures of caracters ? ( hair was cut for chocolat and vanilla )

引用自 klr2701 {fr}：

and just a another question , when we got full pictures of caracters ? ( hair was cut for chocolat and vanilla )

I have explained it in that FAQ post:

Those parts are not drawed at first - in original game, since you don't have any chance to see those parts in such a galgame. :(

ok ok , ty for all response =)