[MC-75309] java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1 (at sa.b(SourceFile:148))

Moderator Note

For some people, reinstalling fixes this issue. To do so, press your Windows+R keys, type in %AppData% at the dialog, and press Enter. In the window that appears, open the .minecraft directory, and delete everything except for the saves directory that you see therein. Then, try running Minecraft again.

[19:48:42] [Client thread/INFO]: Setting user: <username>
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 sa.b(SourceFile:148)
	at sa.<init>(SourceFile:42)
	at net.minecraft.server.MinecraftServer.<init>(SourceFile:154)
	at cyk.<init>(SourceFile:40)
	at bss.<init>(SourceFile:285)
	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