---- Minecraft Crash Report ----
// You're mean.

Time: 8/1/18 5:38 PM
Description: Exception in server tick loop

java.lang.IllegalStateException: Cannot build unresolved tag entry
	at xa$c.a(SourceFile:225)
	at xa.<init>(SourceFile:38)
	at xa$a.b(SourceFile:131)
	at xb.a(SourceFile:135)
	at xc.a(SourceFile:36)
	at vi.c(SourceFile:124)
	at vi.a(SourceFile:107)
	at net.minecraft.server.MinecraftServer.a(SourceFile:1399)
	at net.minecraft.server.MinecraftServer.a(SourceFile:400)
	at dgf.a(SourceFile:83)
	at dgf.d(SourceFile:108)
	at net.minecraft.server.MinecraftServer.run(SourceFile:566)
	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: 18w31a
	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: 423266392 bytes (403 MB) / 637534208 bytes (608 MB) up to 1073741824 bytes (1024 MB)
	JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx1G -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: vanilla, file/ImprovedMC
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.