---- Minecraft Crash Report ----
// You should try our sister game, Minceraft!

Time: 10/26/17 12:40 PM
Description: Exception in server tick loop

java.lang.StringIndexOutOfBoundsException: String index out of range: -2
	at java.lang.String.substring(String.java:1967)
	at nt.a(SourceFile:141)
	at qf.a(SourceFile:116)
	at nt.<init>(SourceFile:61)
	at oo.b(SourceFile:165)
	at chw.a(SourceFile:101)
	at chw.j(SourceFile:133)
	at net.minecraft.server.MinecraftServer.run(SourceFile:467)
	at java.lang.Thread.run(Thread.java:745)


A detailed walkthrough of the error, its code path and all known details is as follows:
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-- System Details --
Details:
	Minecraft Version: 17w43b
	Operating System: Mac OS X (x86_64) version 10.12.6
	Java Version: 1.8.0_74, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 175299880 bytes (167 MB) / 268435456 bytes (256 MB) up to 2147483648 bytes (2048 MB)
	JVM Flags: 7 total; -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	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.