[Server thread/ERROR]: Couldn't save chunk; already in use by another instance of Minecraft?
net.minecraft.server.v1_9_R2.ExceptionWorldConflict: The save for world located at .\world is being accessed from another location, aborting
	at net.minecraft.server.v1_9_R2.WorldNBTStorage.checkSession(WorldNBTStorage.java:78) ~[spigot-1.9.4.jar:git-Spigot-8a048fe-5ff377a]
	at net.minecraft.server.v1_9_R2.World.checkSession(World.java:2816) ~[spigot-1.9.4.jar:git-Spigot-8a048fe-5ff377a]
	at net.minecraft.server.v1_9_R2.ChunkRegionLoader.a(ChunkRegionLoader.java:124) ~[spigot-1.9.4.jar:git-Spigot-8a048fe-5ff377a]
	at net.minecraft.server.v1_9_R2.ChunkProviderServer.saveChunk(ChunkProviderServer.java:229) [spigot-1.9.4.jar:git-Spigot-8a048fe-5ff377a]
	at net.minecraft.server.v1_9_R2.ChunkProviderServer.unloadChunks(ChunkProviderServer.java:302) [spigot-1.9.4.jar:git-Spigot-8a048fe-5ff377a]
	at net.minecraft.server.v1_9_R2.WorldServer.doTick(WorldServer.java:234) [spigot-1.9.4.jar:git-Spigot-8a048fe-5ff377a]
	at net.minecraft.server.v1_9_R2.MinecraftServer.D(MinecraftServer.java:781) [spigot-1.9.4.jar:git-Spigot-8a048fe-5ff377a]
	at net.minecraft.server.v1_9_R2.DedicatedServer.D(DedicatedServer.java:399) [spigot-1.9.4.jar:git-Spigot-8a048fe-5ff377a]
	at net.minecraft.server.v1_9_R2.MinecraftServer.C(MinecraftServer.java:665) [spigot-1.9.4.jar:git-Spigot-8a048fe-5ff377a]
	at net.minecraft.server.v1_9_R2.MinecraftServer.run(MinecraftServer.java:564) [spigot-1.9.4.jar:git-Spigot-8a048fe-5ff377a]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_121]