Minecraft Forums

I have got a error on mc while opening a singleplayer world, my minecraft is not modded but i have used 1.7.10 forge. My version is 1.12.2 and im on windows 10

crash log:

11:48:04
launcher
Preparing to launch minecraft client for 1.12.2


11:48:05
launcher
Checking installations.


11:48:05
launcher
Minecraft client 1.12.2 is ready to start.


11:48:05
launcher
Starting!


11:48:05
launcher
Using default game log configuration client-1.12.xml (outputs XML)


11:48:10
bib
Setting user: zScruffy


11:48:16
bid
Skipping bad option: lastServer:


11:48:16
bib
LWJGL Version: 2.9.4


11:48:18
cev
Reloading ResourceManager: Default


11:48:20
chm
Starting up SoundSystem...


11:48:20
chm
Initializing LWJGL OpenAL


11:48:20
chm
(The LWJGL binding of OpenAL. For more information, see http://www.lwjgl.org)


11:48:28
chm
OpenAL initialized.


11:48:28
chm
Sound engine started


11:48:36
cdp
Created: 1024x512 textures-atlas


11:48:42
com.mojang.text2speech.NarratorWindows
Narrator library for x64 successfully loaded


11:48:44
com.mojang.realmsclient.client.RealmsClient
Could not authorize you against Realms server: Invalid session id


11:48:49
bib
Reported exception thrown!
f: Starting integrated server
at bib.t(SourceFile:1635)
at bib.az(SourceFile:1000)
at bib.a(SourceFile:419)
at net.minecraft.client.main.Main.main(SourceFile:123)
Caused by: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $
at com.google.gson.stream.JsonReader.beginArray(JsonReader.java:350)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:80)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:61)
at rc.a(SourceFile:504)
at rc.a(SourceFile:522)
at ph.b(SourceFile:177)
at ph.<init>(SourceFile:63)
at bib.a(SourceFile:2175)
at bol.e(SourceFile:229)
at bol.a(SourceFile:182)
at bol.a(SourceFile:154)
at bjm.a(SourceFile:41)
at bok.a(SourceFile:117)
at blk.k(SourceFile:400)
at bok.k(SourceFile:49)
at blk.q(SourceFile:377)
at bib.t(SourceFile:1625)
... 3 more

Thank you

Reinstall MC from scratch.