Don't think it is an duplicate with the MC38527.

When I lauch with the latest version I get the error below. If I switch to a 1.7.10/1.7.9 version Minecraft will lauch but will show a gson bug too. Running 1.7.5 seems to work.

On Google I found some hints on changing Java versions etc but this could not resolve it so far.

Cheers Rob

[08:53:23] [Client thread/INFO]: Setting user: XXXXXXX
[08:53:23] [Client thread/INFO]: (Session ID is token:759d3c1d19ac4c03903e8588487bc509:ad4eb04b361646918da255c5314f1acb)
Exception in thread "Client thread" com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1
at com.google.gson.Gson.fromJson(Gson.java:815)
at com.google.gson.Gson.fromJson(Gson.java:768)
at lu.b(SourceFile:151)
at lu.<init>(SourceFile:43)
at net.minecraft.server.MinecraftServer.<init>(SourceFile:155)
at bpp.<init>(SourceFile:41)
at avf.<init>(SourceFile:293)
at net.minecraft.client.main.Main.main(SourceFile:124)
Caused by: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1
at com.google.gson.stream.JsonReader.beginArray(JsonReader.java:338)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:79)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:60)
at com.google.gson.Gson.fromJson(Gson.java:803)
... 7 more
Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release