Keep's crashing.

It won't stop crashing on that version.It keeps saying this in the console "r Something went wrong upgrading!
java.lang.StringIndexOutOfBoundsException: String index out of range: -2
at java.lang.String.substring(String.java:1918)
at yb.a(SourceFile:20)
at wa.b(SourceFile:55)
at wa.a(SourceFile:40)
at boe.a(SourceFile:1004)
at boe.a(SourceFile:776)
at boe.<init>(SourceFile:373)
at bob.an(SourceFile:406)
at bob.a(SourceFile:367)
at net.minecraft.client.main.Main.main(SourceFile:140)"

I dont get it