Put the summary of the bug you're having here

What I expected to happen was...:
Describe what you thought should happen here

What actually happened was...:
Describe what happened here

Steps to Reproduce:
1. i open minecraft
2. i open my world
3.and then crash

---- Minecraft Crash Report ----
// Ouch. That hurt

Time: 5/4/2015 11:49 πμ
Description: Updating screen events

java.lang.IllegalStateException: failed to create a child event loop
at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:68)
at io.netty.channel.MultithreadEventLoopGroup.<init>(MultithreadEventLoopGroup.java:49)
at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:61)
at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:52)
at lm$1.a(SourceFile:44)
at lm$1.b(SourceFile:41)
at np.c(SourceFile:10)
at lm.a(SourceFile:121)
at avf.a(SourceFile:1941)
at axw.i(SourceFile:172)
at axw$a.a(SourceFile:224)
at awj.p(SourceFile:315)
at axw.k(SourceFile:82)
at axv.p(SourceFile:390)
at avf.s(SourceFile:1497)
at avf.av(SourceFile:888)
at avf.a(SourceFile:325)
at net.minecraft.client.main.Main.main(SourceFile:124)
Caused by: io.netty.channel.ChannelException: failed to open a new selector
at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:128)
at io.netty.channel.nio.NioEventLoop.<init>(NioEventLoop.java:120)
at io.netty.channel.nio.NioEventLoopGroup.newChild(NioEventLoopGroup.java:87)
at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:64)
... 17 more
Caused by: java.io.IOException: Unable to establish loopback connection
at sun.nio.ch.PipeImpl$Initializer.run(PipeImpl.java:101)
at sun.nio.ch.PipeImpl$Initializer.run(PipeImpl.java:68)
at java.security.AccessController.doPrivileged(Native Method)
at sun.nio.ch.PipeImpl.<init>(PipeImpl.java:170)
at sun.nio.ch.SelectorProviderImpl.openPipe(SelectorProviderImpl.java:50)
at java.nio.channels.Pipe.open(Pipe.java:155)
at sun.nio.ch.WindowsSelectorImpl.<init>(WindowsSelectorImpl.java:127)
at sun.nio.ch.WindowsSelectorProvider.openSelector(WindowsSelectorProvider.java:44)
at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:126)
... 20 more
Caused by: java.io.IOException: Μια υπάρχουσα σύνδεση διακόπηκε υποχρεωτικά από τον απομακρυσμένο υπολογιστή
at sun.nio.ch.SocketDispatcher.read0(Native Method)
at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:43)
at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223)
at sun.nio.ch.IOUtil.read(IOUtil.java:197)
at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:379)
at sun.nio.ch.PipeImpl$Initializer$LoopbackConnector.run(PipeImpl.java:139)
at sun.nio.ch.PipeImpl$Initializer.run(PipeImpl.java:83)
... 28 more

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

– Head –
Stacktrace:
at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:68)
at io.netty.channel.MultithreadEventLoopGroup.<init>(MultithreadEventLoopGroup.java:49)
at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:61)
at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:52)
at lm$1.a(SourceFile:44)
at lm$1.b(SourceFile:41)
at np.c(SourceFile:10)
at lm.a(SourceFile:121)
at avf.a(SourceFile:1941)
at axw.i(SourceFile:172)
at axw$a.a(SourceFile:224)
at awj.p(SourceFile:315)
at axw.k(SourceFile:82)
at axv.p(SourceFile:390)

– Affected screen –
Details:
Screen name: ayb
Stacktrace:
at avf.s(SourceFile:1497)
at avf.av(SourceFile:888)
at avf.a(SourceFile:325)
at net.minecraft.client.main.Main.main(SourceFile:124)

– System Details –
Details:
Minecraft Version: 1.8.3
Operating System: Windows 7 (amd64) version 6.1
CPU: 8x Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 133786600 bytes (127 MB) / 335056896 bytes (319 MB) up to 1060372480 bytes (1011 MB)
JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
Launched Version: 1.8.3
LWJGL: 2.9.4
OpenGL: GeForce GTX 780/PCIe/SSE2 GL version 4.5.0 NVIDIA 347.52, NVIDIA Corporation
GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

Using VBOs: No
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs: []
Current Language: English (US)
Profiler Position: N/A (disabled)