I couldn't add a new world or join a lan game.

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Minecraft Crash Report ----
// Why did you do that?

Time: 23-7-15 20:59
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 ll$1.a(SourceFile:44)
at ll$1.b(SourceFile:41)
at no.c(SourceFile:10)
at ll.a(SourceFile:121)
at ave.a(SourceFile:1941)
at axv.i(SourceFile:172)
at axv$a.a(SourceFile:224)
at awi.p(SourceFile:315)
at axv.k(SourceFile:82)
at axu.p(SourceFile:390)
at ave.s(SourceFile:1497)
at ave.av(SourceFile:888)
at ave.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.net.SocketException: Permission denied: connect
at sun.nio.ch.Net.connect0(Native Method)
at sun.nio.ch.Net.connect(Net.java:457)
at sun.nio.ch.Net.connect(Net.java:449)
at sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:647)
at java.nio.channels.SocketChannel.open(SocketChannel.java:189)
at sun.nio.ch.PipeImpl$Initializer$LoopbackConnector.run(PipeImpl.java:130)
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 ll$1.a(SourceFile:44)
at ll$1.b(SourceFile:41)
at no.c(SourceFile:10)
at ll.a(SourceFile:121)
at ave.a(SourceFile:1941)
at axv.i(SourceFile:172)
at axv$a.a(SourceFile:224)
at awi.p(SourceFile:315)
at axv.k(SourceFile:82)
at axu.p(SourceFile:390)

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

– System Details –
Details:
Minecraft Version: 1.8.7
Operating System: Windows 8.1 (amd64) version 6.3
CPU: 4x Intel(R) Celeron(R) CPU N2940 @ 1.83GHz
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 88323752 bytes (84 MB) / 291700736 bytes (278 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: 1.8.7
LWJGL: 2.9.4
OpenGL: Intel(R) HD Graphics GL version 4.0.0 - Build 10.18.10.3910, Intel
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)

Thank you for your report.
However, your ticket has been resolved as a duplicate.

This issue has been linked to the original bugreport: MC-34749. You can find or add further information on that report.
Please search before reporting any bugs, as it's likely that one exists already.