first time i play minceraft at 1.8.9, and i download optifine and forge, then now i dowwnload 1.12 forge with optifine. when i want play 1.8.9 it keep crashed

here the crash reports

---- Minecraft Crash Report ----

WARNING: coremods are present:
Contact their authors BEFORE contacting forge

// Don't be sad. I'll do better next time, I promise!

Time: 6/23/17 9:25 AM
Description: Initializing game

java.lang.NoClassDefFoundError: cep
    at java.lang.Class.getDeclaredFields0(Native Method)
    at java.lang.Class.privateGetDeclaredFields(Unknown Source)
    at java.lang.Class.getField0(Unknown Source)
    at java.lang.Class.getField(Unknown Source)
    at net.minecraftforge.fml.client.FMLClientHandler.detectOptifine(FMLClientHandler.java:277)
    at net.minecraftforge.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:191)
    at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:417)
    at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:329)
    at net.minecraft.client.main.Main.main(SourceFile:124)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
    at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
Caused by: java.lang.ClassNotFoundException: cep
    at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 15 more
Caused by: java.lang.NullPointerException
    at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:182)
    ... 17 more

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
    at java.lang.Class.getDeclaredFields0(Native Method)
    at java.lang.Class.privateGetDeclaredFields(Unknown Source)
    at java.lang.Class.getField0(Unknown Source)
    at java.lang.Class.getField(Unknown Source)
    at net.minecraftforge.fml.client.FMLClientHandler.detectOptifine(FMLClientHandler.java:277)
    at net.minecraftforge.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:191)
    at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:417)

-- Initialization --
Details:
Stacktrace:
    at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:329)
    at net.minecraft.client.main.Main.main(SourceFile:124)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
    at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

-- System Details --
Details:
    Minecraft Version: 1.8.9
    Operating System: Windows 10 (x86) version 10.0
    Java Version: 1.8.0_66, Oracle Corporation
    Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
    Memory: 64697120 bytes (61 MB) / 225103872 bytes (214 MB) up to 523501568 bytes (499 MB)
    JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
    IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
    FML: 
    Loaded coremods (and transformers): 
    Launched Version: 1.8.9-forge1.8.9-11.15.1.1722
    LWJGL: 2.9.4
    OpenGL: AMD Radeon HD 7310 Graphics GL version 4.5.13399 Compatibility Profile Context 15.201.1151.0, ATI Technologies Inc.
    GL Caps: Using GL 1.3 multi

 

pls give me the solution thanks

You probably still have the 1.12 version of Optifine installed in the same mods directory used by your 1.8.9 profile.

 

You should set each profile to have its own game directory in the launcher, allowing them to have their own set of mods installed.

so what i must do? delete the optifine or what?

4 hours ago, DazDrag said:

so what i must do? delete the optifine or what?

 

On 2017-6-23 at 4:13 PM, Choonster said:

You should set each profile to have its own game directory in the launcher, allowing them to have their own set of mods installed.

 

Once you've done this, make sure you don't install 1.11.2 mods in the 1.8.9 profile and vice versa.