[SOLVED] Unity Window : ArgumentException: Object at index 0 is null

Hi, I got this error for any unknown reason after about 10 times go into play mode in Editor.
Error then repeat every time when go into play mode.

Does also happen in 2019.1.7f1.



ArgumentException: Object at index 0 is null
UnityEditor.SerializedObject..ctor (UnityEngine.Object[] objs, UnityEngine.Object context) (at C:/buildslave/unity/build/Editor/Mono/SerializedObject.bindings.cs:39)
UnityEditor.Editor.GetSerializedObjectInternal () (at C:/buildslave/unity/build/Editor/Mono/Inspector/Editor.cs:553)
UnityEditor.Editor.get_serializedObject () (at C:/buildslave/unity/build/Editor/Mono/Inspector/Editor.cs:452)
UnityEditor.UIElements.InspectorElement..ctor (UnityEditor.Editor editor, UnityEditor.UIElements.InspectorElement+Mode mode) (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorElement.cs:133)
UnityEditor.UIElements.EditorElement.Init () (at C:/buildslave/unity/build/Editor/Mono/Inspector/EditorElement.cs:86)
UnityEditor.UIElements.EditorElement..ctor (System.Int32 editorIndex, UnityEditor.InspectorWindow iw) (at C:/buildslave/unity/build/Editor/Mono/Inspector/EditorElement.cs:64)
UnityEditor.InspectorWindow.DrawEditors (UnityEditor.Editor[] editors) (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:1392)
UnityEditor.InspectorWindow.RebuildContentsContainers () (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:639)
UnityEditor.InspectorWindow.RedrawFromNative () (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:311)

 

It seems the error comes up if a second inspector window is open.

 

This helped me a lot, worked for me but you have to restart unity.

 

Wow yes. Very handy. After restarting, and removing the second inspector window, the mystery error goes away. Thanks thanks.

 

I am also getting this same error but I do not have a second inspector window open.

 

Wow, I was quite uneasy because I'm in a hutty and it popped me after being playing with serialiazing some json, and first thought was I messed something up.

But it was just the second inspector tab. Big thanks to @Quatum1000

 

I could swear I had seen an open bug report for this but I can't find it anymore.

Is it somewhere in the issue tracker @LeonhardP ?

Also, it seems to happen if you create a GameObject editor from script.

 

We're getting a similar error after working on customised timeline signals:

SerializedObjectNotCreatableException: Object at index 0 is null
UnityEditor.Editor.CreateSerializedObject () (at C:/buildslave/unity/build/Editor/Mono/Inspector/Editor.cs:577)
UnityEditor.Editor.GetSerializedObjectInternal () (at C:/buildslave/unity/build/Editor/Mono/Inspector/Editor.cs:554)
UnityEditor.Editor.get_serializedObject () (at C:/buildslave/unity/build/Editor/Mono/Inspector/Editor.cs:453)
UnityEditor.Timeline.Signals.SignalReceiverInspector.OnEnable () (at C:/Program Files/Unity/Hub/Editor/2019.2.17f1/Editor/Data/Resources/PackageManager/BuiltInPackages/com.unity.timeline/Editor/Signals/SignalReceiverInspector.cs:28)

The error doesn't appear in 2019.2.6f1 but does after porting the content to a project using the latest Unity 2019.2.17f1.
We don't have two Inspector windows open as discussed above. I've tried closing the inspector panel and closing the timeline panel but this doesn't fix things.

I've attached our SignalReceiverWithInt class which may be the source of the problem. Perhaps the serialization tags need tweaked?

Thanks for any input.

 

I'm also getting this error. In my case I have a custom node graph implementation using UIElements, and the graph is represented as a prefab with a bunch of child gameObjects as nodes. It is always accompanied by this other exception:

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.GameObjectInspector.ClearPreviewCache () (at <83a73882c51c4602b3d34743827d03e7>:0)
UnityEditor.GameObjectInspector.OnDisable () (at <83a73882c51c4602b3d34743827d03e7>:0)

 

I just updated to 2018.4.16f1 and this started appearing when I have Squiggle open when entering playmode. Yay.

 

Seem the issue happen if a editor window access an existing window and try to share it's instance. From 2019.2 it never appears again to me.

 

It happens to me if I have a game object that has a code script as a component (and therefore inspecting) when I hit Play on v2019.2.0f1.

 

Yes, closing the second inspector window SOLVED this for me as well.

Still, there is a bug for those of you developing the tool.