Since updating to 780 I have been having this happen, somewhat often. I have tried downgrading, but it is still going on. The other upgrades to mods I had done have alos been downgraded, problem still persists. In addition, the wrench sound plays repeatedly and randomly, even when in another dimension and away from my factory. I believe this is the sound file causing the crash, but not sure.
Not sure that this is IC2 EXP, but I think it might be. If anyone has any information on this, a solution would be appreciated.
---- Minecraft Crash Report ----
// Uh... Did I do that?
Time: 10/10/15 5:24 PM
Description: Unexpected error
java.util.ConcurrentModificationException
at com.google.common.collect.HashBiMap$Itr.checkForConcurrentModification(HashBiMap.java:339)
at com.google.common.collect.HashBiMap$Itr.hasNext(HashBiMap.java:345)
at net.minecraft.client.audio.SoundManager.func_148605_d(SoundManager.java:212)
at net.minecraft.client.audio.SoundHandler.func_73660_a(SourceFile:179)
at net.minecraft.client.Minecraft.func_71407_l(Minecraft.java:2013)
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:973)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:898)
at net.minecraft.client.main.Main.main(SourceFile:148)
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)