---- Minecraft Crash Report ----
// I just don't know what went wrong :(

Time: 10/5/16 9:14 PM
Description: Exception ticking world

java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.remove(HashMap.java:1443)
	at lr.d(SourceFile:198)
	at ls.d(SourceFile:202)
	at net.minecraft.server.MinecraftServer.D(SourceFile:618)
	at net.minecraft.server.MinecraftServer.C(SourceFile:554)
	at bzl.C(SourceFile:155)
	at net.minecraft.server.MinecraftServer.run(SourceFile:458)
	at java.lang.Thread.run(Thread.java:745)


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

-- Head --
Thread: Server thread
Stacktrace:
	at java.util.HashMap$HashIterator.remove(HashMap.java:1443)
	at lr.d(SourceFile:198)
	at ls.d(SourceFile:202)

-- Affected level --
Details:
	Level name: Cat
	All players: 0 total; []
	Chunk stats: ServerChunkCache: 538 Drop: 284
	Level seed: -505246733402235234
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (140,64,256), Chunk: (at 12,4,0 in 8,16; contains blocks 128,0,256 to 143,255,271), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 533495 game time, 631247 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 21396 (now: false), thunder time: 71553 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
	at net.minecraft.server.MinecraftServer.D(SourceFile:618)
	at net.minecraft.server.MinecraftServer.C(SourceFile:554)
	at bzl.C(SourceFile:155)
	at net.minecraft.server.MinecraftServer.run(SourceFile:458)
	at java.lang.Thread.run(Thread.java:745)

-- System Details --
Details:
	Minecraft Version: 1.10.2
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.8.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 161005936 bytes (153 MB) / 375889920 bytes (358 MB) up to 1060372480 bytes (1011 MB)
	JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
	Profiler Position: N/A (disabled)
	Player Count: 0 / 8; []
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.