---- Minecraft Crash Report ----
// My bad.

Time: 29/06/18 22:30
Description: Exception in server tick loop

java.lang.IllegalStateException: Cannot build unresolved tag entry
	at wt$c.a(SourceFile:225)
	at wt.<init>(SourceFile:38)
	at wt$a.b(SourceFile:131)
	at wu.a(SourceFile:135)
	at wv.a(SourceFile:36)
	at vb.c(SourceFile:123)
	at vb.a(SourceFile:106)
	at net.minecraft.server.MinecraftServer.a(SourceFile:1361)
	at net.minecraft.server.MinecraftServer.a(SourceFile:355)
	at dej.a(SourceFile:82)
	at dej.d(SourceFile:132)
	at net.minecraft.server.MinecraftServer.run(SourceFile:505)
	at java.lang.Thread.run(Thread.java:745)


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

-- System Details --
Details:
	Minecraft Version: 1.13-pre5
	Operating System: Windows 10 (amd64) version 10.0
	Java Version: 1.8.0_51, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 333678864 bytes (318 MB) / 503316480 bytes (480 MB) up to 4294967296 bytes (4096 MB)
	JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx4G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=16M
	Profiler Position: N/A (disabled)
	Player Count: 0 / 8; []
	Data Packs: file/Hardel.zip (incompatible)
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.