I have the problem that if I start Minecraft with Forge the following error message comes.
It looks like you're using an unsupported, modified version of the game.
The game crashed while initializing game.
I need to be more specific.
But I guess you did not use the same version for everything.
Taking the same version in everything is very important.
So if I open the launcher everything is still normal but if I then press play on the game starts but then it crashes and then comes the error message oh yes and I have everything in the same version