Hi,

I installed Forge 1.7.2, started minecraft and it crashed. Then i installed OptiFine 1.7.2 and it dit the same. Here is the error that the launcher said:

 

[12:24:59] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLTweaker

[12:24:59] [main/INFO] [LaunchWrapper]: Using primary tweak class name cpw.mods.fml.common.launcher.FMLTweaker

[12:24:59] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.common.launcher.FMLTweaker

[12:24:59] [main/INFO] [FML]: Forge Mod Loader version 7.2.211.1121 for Minecraft 1.7.2 loading

[12:24:59] [main/INFO] [FML]: Java is Java HotSpot 64-Bit Server VM, version 1.7.0_13, running on Windows 7:amd64:6.1, installed at C:\Program Files\Java\jre7

[12:24:59] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker

[12:24:59] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLDeobfTweaker

[12:24:59] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker

[12:24:59] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker

[12:24:59] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.relauncher.CoreModManager$FMLPluginWrapper

[12:25:01] [main/INFO] [FML]: Found valid fingerprint for Minecraft Forge. Certificate fingerprint e3c3d50c7c986df74c645c0ac54639741c90a557

[12:25:01] [main/ERROR] [FML]: The minecraft jar file:/C:/Users/Victor/AppData/Roaming/.minecraft/versions/1.7.2-Forge10.12.2.1121/1.7.2-Forge10.12.2.1121.jar!/net/minecraft/client/ClientBrandRetriever.class appears to be corrupt! There has been CRITICAL TAMPERING WITH MINECRAFT, it is highly unlikely minecraft will work! STOP NOW, get a clean copy and try again!

[12:25:01] [main/ERROR] [FML]: For your safety, FML will not launch minecraft. You will need to fetch a clean version of the minecraft jar file

[12:25:01] [main/ERROR] [FML]: Technical information: The class net.minecraft.client.ClientBrandRetriever should have been associated with the minecraft jar file, and should have returned us a valid, intact minecraft jar location. This did not work. Either you have modified the minecraft jar file (if so run the forge installer again), or you are using a base editing jar that is changing this class (and likely others too). If you REALLY want to run minecraft in this configuration, add the flag -Dfml.ignoreInvalidMinecraftCertificates=true to the 'JVM settings' in your launcher profile.

 

I hope that anyone could fix this for me. Already thanks.

get a clean copy and try again

http://files.minecraftforge.net/

get a clean copy and try again

http://files.minecraftforge.net/

I already did this about 3 times, it doesnt work for me.

add the flag -Dfml.ignoreInvalidMinecraftCertificates=true to the 'JVM settings' in your launcher profile.

 

learn2readlogs

how did you install optifine ?

Reinstall forge and vanilla,  do not edit the jars in any way.

Make sure it works.

Then just put optifine into the mods folder.