[05:01:11] [File IO Thread/ERROR]: Failed to save chunk
java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextNode(Unknown Source) ~[?:1.8.0_102]
	at java.util.HashMap$KeyIterator.next(Unknown Source) ~[?:1.8.0_102]
	at net.minecraft.nbt.NBTTagCompound.func_74734_a(NBTTagCompound.java:23) ~[dr.class:?]
	at net.minecraft.nbt.CompressedStreamTools.func_150663_a(CompressedStreamTools.java:111) ~[ea.class:?]
	at net.minecraft.nbt.CompressedStreamTools.func_74800_a(CompressedStreamTools.java:101) ~[ea.class:?]
	at net.minecraft.world.chunk.storage.AnvilChunkLoader.func_183013_b(AnvilChunkLoader.java:242) ~[atj.class:?]
	at net.minecraft.world.chunk.storage.AnvilChunkLoader.func_75814_c(AnvilChunkLoader.java:220) [atj.class:?]
	at net.minecraft.world.storage.ThreadedFileIOBase.func_75736_b(SourceFile:37) [bbu.class:?]
	at net.minecraft.world.storage.ThreadedFileIOBase.run(SourceFile:30) [bbu.class:?]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_102]