The game crashed whilst mouseclicked event handler
Error: java.lang.IllegalStateException: failed to create a child event loop
Crash report:
Minecraft Crash Report -------- Minecraft Crash Report ----// There are four lights!
Time: 8/1/19 4:50 PMDescription: mouseClicked event handler
java.lang.IllegalStateException: failed to create a child event loop at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:88) at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:58) at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:47) at io.netty.channel.MultithreadEventLoopGroup.<init>(MultithreadEventLoopGroup.java:59) at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:77) at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:72) at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:59) at wb.f(SourceFile:55) at wb$$Lambda$2359/3392912.get(Unknown Source) at zv.a(SourceFile:16) at wb.a(SourceFile:136) at cyc.a(SourceFile:1640) at dfu$a.e(SourceFile:380) at dfu$a.a(SourceFile:311) at dfu$a.mouseClicked(SourceFile:252) at cze.mouseClicked(SourceFile:322) at dad.mouseClicked(SourceFile:27) at cyd.b(SourceFile:86) at cyd$$Lambda$1749/978218406.run(Unknown Source) at dcl.wrapScreenError(SourceFile:441) at cyd.a(SourceFile:86) at cyd$$Lambda$1454/549417478.invoke(Unknown Source) at org.lwjgl.glfw.GLFWMouseButtonCallbackI.callback(GLFWMouseButtonCallbackI.java:36) at org.lwjgl.system.JNI.invokeV(Native Method) at org.lwjgl.glfw.GLFW.glfwWaitEventsTimeout(GLFW.java:3174) at cuo.c(SourceFile:291) at cyc.b(SourceFile:1027) at cyc.e(SourceFile:976) at cyc.b(SourceFile:410) at net.minecraft.client.main.Main.main(SourceFile:155)Caused by: io.netty.channel.ChannelException: failed to open a new selector at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:177) at io.netty.channel.nio.NioEventLoop.<init>(NioEventLoop.java:151) at io.netty.channel.nio.NioEventLoopGroup.newChild(NioEventLoopGroup.java:127) at io.netty.channel.nio.NioEventLoopGroup.newChild(NioEventLoopGroup.java:36) at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:84) ... 29 moreCaused 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:175) ... 33 moreCaused by: java.net.ConnectException: Connection timed out: connect at sun.nio.ch.Net.connect0(Native Method) at sun.nio.ch.Net.connect(Net.java:458) at sun.nio.ch.Net.connect(Net.java:450) at sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:648) 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) ... 41 more
A detailed walkthrough of the error, its code path and all known details is as follows:---------------------------------------------------------------------------------------
– Head --Thread: Client threadStacktrace: at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:88) at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:58) at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:47) at io.netty.channel.MultithreadEventLoopGroup.<init>(MultithreadEventLoopGroup.java:59) at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:77) at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:72) at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:59) at wb.f(SourceFile:55) at wb$$Lambda$2359/3392912.get(Unknown Source) at zv.a(SourceFile:16) at wb.a(SourceFile:136) at cyc.a(SourceFile:1640) at dfu$a.e(SourceFile:380) at dfu$a.a(SourceFile:311) at dfu$a.mouseClicked(SourceFile:252) at cze.mouseClicked(SourceFile:322) at dad.mouseClicked(SourceFile:27) at cyd.b(SourceFile:86) at cyd$$Lambda$1749/978218406.run(Unknown Source)
– Affected screen --Details: Screen name: dftStacktrace: at dcl.wrapScreenError(SourceFile:441) at cyd.a(SourceFile:86) at cyd$$Lambda$1454/549417478.invoke(Unknown Source) at org.lwjgl.glfw.GLFWMouseButtonCallbackI.callback(GLFWMouseButtonCallbackI.java:36) at org.lwjgl.system.JNI.invokeV(Native Method) at org.lwjgl.glfw.GLFW.glfwWaitEventsTimeout(GLFW.java:3174) at cuo.c(SourceFile:291) at cyc.b(SourceFile:1027) at cyc.e(SourceFile:976) at cyc.b(SourceFile:410) at net.minecraft.client.main.Main.main(SourceFile:155)
– System Details --Details: Minecraft Version: 1.14.4 Minecraft Version ID: 1.14.4 Operating System: Windows 10 (amd64) version 10.0 Java Version: 1.8.0_51, Oracle Corporation Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation Memory: 1184049400 bytes (1129 MB) / 2046820352 bytes (1952 MB) up to 2147483648 bytes (2048 MB) CPUs: 4 JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M Launched Version: 1.14.4 LWJGL: 3.2.2 build 10 OpenGL: GeForce GTX 1050 Ti/PCIe/SSE2 GL version 4.6.0 NVIDIA 430.86, 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: Yes Is Modded: Probably not. Jar signature remains and client brand is untouched. Type: Client (map_client.txt) Resource Packs: Current Language: English (US) CPU: 4x Intel(R) Core(TM) i5-4440 CPU @ 3.10GHz
I tried to fix it, but none of the "solutions" worked.
Things I tried:
-netsh winsock reset in cmd
-reinstalling minecraft
-disabling antivirus and firewall
Related issues
Comments

I tried to use that JVM Argument and I also tried to turn the private network off. It didn't work as well
If your issue is still not resolved, please do the following from this comment.

I have this problem but I try all method how I can resolve this problem?

hello I have tried all the possible methods or the following: changed Java version, updated the drivers, entered two different codes in the cmd, changed Launcher, entered a code on the Launcher, disabled antivirus / firewall, canceled Mcafee. but I still have your same problem, help me

I also currently experience this problem. I have to re-install Minecraft to get one good session. If I exit and try to start again, I can't connect to any server and if I try to enter my singleplayer worlds it crashes and says failed to create child event loop.
See MC-34749 (This comment might also help https://bugs.mojang.com/browse/MC-156124?focusedCommentId=563758&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-563758).