for some reason my server crashed. Here is the log. ---- Minecraft Crash Report ---- // Sorry Time: 12/7/14 1:54 PM Description: Exception in server tick loop net.minecraft.server.v1_7_R3.ExceptionWorldConflict: Failed to check session lock, aborting at net.minecraft.server.v1_7_R3.WorldNBTStorage.checkSession(WorldNBTStorage.java:78) at net.minecraft.server.v1_7_R3.World.G(World.java:2626) at net.minecraft.server.v1_7_R3.WorldServer.a(WorldServer.java:790) at net.minecraft.server.v1_7_R3.WorldServer.save(WorldServer.java:763) at net.minecraft.server.v1_7_R3.MinecraftServer.saveChunks(MinecraftServer.java:369) at net.minecraft.server.v1_7_R3.MinecraftServer.u(MinecraftServer.java:576) at net.minecraft.server.v1_7_R3.MinecraftServer.run(MinecraftServer.java:469) at net.minecraft.server.v1_7_R3.ThreadServerApplication.run(SourceFile:628)