When I tried to load a singleplayer world it crashes.
[15:12:53] [Server thread/ERROR]: Encountered an unexpected exception
[15:12:53 INFO]: Client> q: Exception getting block type in world
[15:12:53 INFO]: Client> at nv.c(SourceFile:147) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at net.minecraft.server.MinecraftServer.v(SourceFile:545) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at net.minecraft.server.MinecraftServer.u(SourceFile:461) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at byn.u(SourceFile:123) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at net.minecraft.server.MinecraftServer.run(SourceFile:377) [14w04a.jar:?]
[15:12:53 INFO]: Client> at mc.run(SourceFile:647) [14w04a.jar:?]
[15:12:53 INFO]: Client> Caused by: java.lang.RuntimeException: Already decorating
[15:12:53 INFO]: Client> at ail.a(SourceFile:21) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at aif.a(SourceFile:386) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at ain.a(SourceFile:29) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at asc.a(SourceFile:443) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at nl.a(SourceFile:174) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at aqz.a(SourceFile:834) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at nl.c(SourceFile:103) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at nl.d(SourceFile:116) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at ahn.b(SourceFile:273) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at ahn.f(SourceFile:268) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at ahn.c(SourceFile:204) ~[14w04a.jar:?]
[15:12:53 INFO]: Client> at ahn.d(SourceFile:219) ~[14w04a.jar:?]
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Attached the dev console output. I have the launcher shown by default just in case something like this happens
Please attach the complete output of the "Development console" which can be found on the second tab of the launcher.
If the launcher closes after game start, please edit your profile and select "Launcher visibility" then, "Keep the launcher open".