[16:58:31] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.util.ConcurrentModificationException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at net.minecraft.util.Util.func_181617_a(SourceFile:46) [h.class:?]
	at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:1045) [bcx.class:?]
	at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:371) [bcx.class:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [Main.class:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_25]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_25]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_25]
	at java.lang.reflect.Method.invoke(Method.java:483) ~[?:1.8.0_25]
	at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
	at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
Caused by: java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextNode(HashMap.java:1429) ~[?:1.8.0_25]
	at java.util.HashMap$KeyIterator.next(HashMap.java:1453) ~[?:1.8.0_25]
	at net.minecraft.util.ClassInheritanceMultiMap.<init>(SourceFile:26) ~[ob.class:?]
	at net.minecraft.world.chunk.Chunk.<init>(Chunk.java:88) ~[asv.class:?]
	at net.minecraft.client.multiplayer.ChunkProviderClient.func_73158_c(ChunkProviderClient.java:60) ~[blj.class:?]
	at net.minecraft.client.multiplayer.WorldClient.func_73025_a(WorldClient.java:184) ~[bln.class:?]
	at net.minecraft.client.network.NetHandlerPlayClient.func_147263_a(NetHandlerPlayClient.java:708) ~[bll.class:?]
	at net.minecraft.network.play.server.SPacketChunkData.func_148833_a(SourceFile:96) ~[gt.class:?]
	at net.minecraft.network.play.server.SPacketChunkData.func_148833_a(SourceFile:18) ~[gt.class:?]
	at net.minecraft.network.PacketThreadUtil$1.run(SourceFile:13) ~[fl$1.class:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_25]
	at net.minecraft.util.Util.func_181617_a(SourceFile:45) ~[h.class:?]
	... 9 more