Game crashes after building terrain but before starting

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 md$1.a(SourceFile:61)
	at md$1.b(SourceFile:58)
	at ol.c(SourceFile:10)
	at md.a(SourceFile:138)
	at bcx.a(SourceFile:2158)
	at bif.e(SourceFile:227)
	at bif.a(SourceFile:182)
	at bif.a(SourceFile:148)
	at bed.b(SourceFile:41)
	at bie.a(SourceFile:118)
	at bft.k(SourceFile:409)
	at bie.k(SourceFile:50)
	at bft.p(SourceFile:386)
	at bcx.t(SourceFile:1586)
	at bcx.av(SourceFile:968)
	at bcx.a(SourceFile:396)
	at net.minecraft.client.main.Main.main(SourceFile:124)
Caused by: io.netty.channel.ChannelException: failed to open a new selector
	at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:128)
	at io.netty.channel.nio.NioEventLoop.<init>(NioEventLoop.java:120)
	at io.netty.channel.nio.NioEventLoopGroup.newChild(NioEventLoopGroup.java:87)
	at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:64)
	... 20 more
Caused by: java.io.IOException: Unable to establish loopback connection
	at sun.nio.ch.PipeImpl$Initializer.run(PipeImpl.java:101)
	at sun.nio.ch.PipeImpl$Initializer.run(PipeImpl.java:68)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.nio.ch.PipeImpl.<init>(PipeImpl.java:170)
	at sun.nio.ch.SelectorProviderImpl.openPipe(SelectorProviderImpl.java:50)
	at java.nio.channels.Pipe.open(Pipe.java:155)
	at sun.nio.ch.WindowsSelectorImpl.<init>(WindowsSelectorImpl.java:127)
	at sun.nio.ch.WindowsSelectorProvider.openSelector(WindowsSelectorProvider.java:44)
	at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:126)
	... 23 more
Caused by: java.io.IOException: An existing connection was forcibly closed by the remote host
	at sun.nio.ch.SocketDispatcher.read0(Native Method)
	at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:43)
	at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223)
	at sun.nio.ch.IOUtil.read(IOUtil.java:197)
	at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:379)
	at sun.nio.ch.PipeImpl$Initializer$LoopbackConnector.run(PipeImpl.java:139)
	at sun.nio.ch.PipeImpl$Initializer.run(PipeImpl.java:83)
	... 31 more