i dont know what happened it just starts then back to the launcher everytime
this is what it says when it returned to launcher:
GameStarter running! net.minecraft.launchwrapper.Launch
[10:16:06] [main/INFO]: Loading tweak class name net.minecraftforge.fml.common.launcher.FMLTweaker
[10:16:06] [main/ERROR]: Unable to launch
java.lang.ClassNotFoundException: net.minecraftforge.fml.common.launcher.FMLTweaker
at java.net.URLClassLoader.findClass(Unknown Source) ~[?:1.8.0_211]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_211]
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) ~[?:1.8.0_211]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_211]
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:106) ~[launchwrapper-1.12.jar:?]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_211]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_211]
at java.lang.Class.forName0(Native Method) ~[?:1.8.0_211]
at java.lang.Class.forName(Unknown Source) ~[?:1.8.0_211]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:98) [launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_211]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_211]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_211]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_211]
at info.mineshafter.GameStarter.main(GameStarter.java:33) [ms-starter.jar:?]
Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release
Edit : i tried opening minecraft 1.12.2 it crashed
Minecraft: Minecraft 1.2.2
OS: Windows 7 (amd64) version 6.1
Java: 1.8.0_211, Oracle Corporation
VM: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
LWJGL: 2.9.0
OpenGL: Intel(R) HD Graphics version 2.1.0 - Build 8.15.10.2993, Intel
java.lang.NullPointerException
at java.io.Reader.<init>(Unknown Source)
at java.io.InputStreamReader.<init>(Unknown Source)
at adi.a(SourceFile:62)
at adi.a(SourceFile:99)
at net.minecraft.client.Minecraft.a(SourceFile:256)
at net.minecraft.client.Minecraft.run(SourceFile:650)
at java.lang.Thread.run(Unknown Source)
--- END ERROR REPORT 3621864e ----------
