Minecraft Forge 1.12 crash fix with new launcher?

Hi as in the question I would like to fix the constant crashes in the new launcher, but unfortunately there's nowhere on the net anything (except with the old launcher) I come into the game but as soon as I want to load the world you throw me again back to the launcher with this error:

The game crashed while exception in server tick loop

The game crashed while exception in server tick loop

Error: java.lang.NoSuchMethodError: net.minecraft.entity.EntityLiving $ SpawnPlacementType.canSpawnAt (Lnet / minecraft / world / World; Lnet / minecraft / util / math / BlockPos;) Z

I use the latest version of 1.12 Forge and the mods are also all current. And Minecraft is also already installed. I hope someone can help because I would like to play with mods. P.S Play it on a laptop.

If you have not already done so, you can delete the ".minecraft" Odner. You just have to press the Windows key + R and then enter% appdata%, then a window should open with many odnern, the top will then be the. Minecraft folder. Just delete that BUT before you delete that you should backup important things like worlds so that they are not gone.

That can solve many problems.

I'll test that thank you. The funny thing is that it has no problems with lower versions.

If you delete .minecraft the game will break! This is not an answer!

It happened to me when installing Optifine 1.12.2.

Optifine keeps crashing my game so I think that could be one (or) the answer.

I dont want to delete .minecraft folder becasue Im scared to lose the things there and I dont know how to create a backup