Minecraft ne se lance plus

Bonjour,

Je vous joins ce que j'obtiens à l'écran :

Dans Minecraft Launcher 1.6.48

Game Output

Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release
Completely ignored arguments: [--nativeLauncherVersion, 285]
[23:46:15] [Client thread/INFO]: Setting user: haddock63
[23:46:15] [Client thread/INFO]: (Session ID is token:c0ec63e332a044b2968a0fdcb2fe6f4d:21b1d79a7f67463fa77adbadaa44924d)
Exception in thread "Client thread" java.lang.NullPointerException
at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:213)
at com.google.common.collect.Lists$ReverseList.<init>(Lists.java:767)
at com.google.common.collect.Lists.reverse(Lists.java:759)
at lt.b(SourceFile:156)
at lt.<init>(SourceFile:43)
at net.minecraft.server.MinecraftServer.<init>(SourceFile:155)
at bpo.<init>(SourceFile:41)
at ave.<init>(SourceFile:293)
at net.minecraft.client.main.Main.main(SourceFile:124)

Merci de votre aide, c'est pour mon fils qui n'en peut plus...