Cresh report login SinglePlayer. 18w09a

to reproduce :
1 start minecraft.
2. open old world.

Crash :

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

Time: 03/03/18 18:34
Description: Loading entity NBT

i: Non [a-z0-9/._-] character in path of location: ecraft:dropper                             
	at nz.<init>(SourceFile:36)
	at nz.<init>(SourceFile:41)
	at vi.a(SourceFile:98)
	at sb.a(SourceFile:206)
	at abg.f(SourceFile:1560)
	at buq.b(SourceFile:176)
	at uk.a(SourceFile:300)
	at uk.a(SourceFile:124)
	at sz.b(SourceFile:119)
	at sz.aa_(SourceFile:66)
	at hi.a(SourceFile:221)
	at sw.c(SourceFile:175)
	at net.minecraft.server.MinecraftServer.w(SourceFile:720)
	at net.minecraft.server.MinecraftServer.v(SourceFile:627)
	at cxk.v(SourceFile:155)
	at net.minecraft.server.MinecraftServer.run(SourceFile:532)
	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 nz.<init>(SourceFile:36)
	at nz.<init>(SourceFile:41)
	at vi.a(SourceFile:98)
	at sb.a(SourceFile:206)

-- Entity being loaded --
Details:
	Entity Type: minecraft:player (sb)
	Entity ID: 1
	Entity Name: Erisium_Hardel
	Entity's Exact location: 0,00, 0,00, 0,00
	Entity's Block location: World: (0,0,0), Chunk: (at 0,0,0 in 0,0; contains blocks 0,0,0 to 15,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Entity's Momentum: 0,00, 0,00, 0,00
	Entity's Passengers: []
	Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
	at abg.f(SourceFile:1560)
	at buq.b(SourceFile:176)
	at uk.a(SourceFile:300)
	at uk.a(SourceFile:124)
	at sz.b(SourceFile:119)
	at sz.aa_(SourceFile:66)
	at hi.a(SourceFile:221)

-- Ticking connection --
Details:
	Connection: hi@20c3b404
Stacktrace:
	at sw.c(SourceFile:175)
	at net.minecraft.server.MinecraftServer.w(SourceFile:720)
	at net.minecraft.server.MinecraftServer.v(SourceFile:627)
	at cxk.v(SourceFile:155)
	at net.minecraft.server.MinecraftServer.run(SourceFile:532)
	at java.lang.Thread.run(Thread.java:745)

-- System Details --
Details:
	Minecraft Version: 18w09a
	Operating System: Windows 10 (amd64) version 10.0
	Java Version: 1.8.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 103020624 bytes (98 MB) / 251658240 bytes (240 MB) up to 1073741824 bytes (1024 MB)
	JVM Flags: 8 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -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/classe (incompatible)
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.