Error executing task on Client: Playing level event

Error executing task on Client
l: Playing level event
    at dgf.a(SourceFile:599)
    at bfx.c(SourceFile:1252)
    at dgc.a(SourceFile:1254)
    at ll.a(SourceFile:45)
    at ll.a(SourceFile:10)
    at kb.a(SourceFile:15)
    at kb$$Lambda$2698/435904118.run(Unknown Source)
    at afy.g(SourceFile:122)
    at agc.g(SourceFile:23)
    at afy.p(SourceFile:101)
    at afy.bf(SourceFile:86)
    at ctp.d(SourceFile:931)
    at ctp.b(SourceFile:413)
    at net.minecraft.client.main.Main.main(SourceFile:154)
Caused by: java.lang.NullPointerException
    at dgf.a(SourceFile:475)
    at dgf.a(SourceFile:470)
    at djg.a(SourceFile:2604)
    at dgf.a(SourceFile:589)
    ... 13 more