null refrence error

I'm getting this error:
NullReferenceException: Object reference not set to an instance of an object
UnityEditor.InspectorWindow.OnSelectionChange () (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:147)
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:222)
Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation.
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:232)
System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MethodBase.cs:115)
UnityEditor.HostView.Invoke (System.String methodName, System.Object obj) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:295)
UnityEditor.HostView.Invoke (System.String methodName) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:288)
UnityEditor.HostView.OnSelectionChange () (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:168)
UnityEditorInternal.VisualStudioUtil:FindVisualStudioDevEnvPaths(Int32, String[])
UnityEditor.EditorAssembliesrocessInitializeOnLoadAttributes()
Does anyone have any idea what's causing it?

 

Sorry about the emoji, That was a complete accident, that place is meant to read: EditorAssemblies: ProcessInitializeOnLoadAttributes()

 

Have you reported it?

 

Why would I report an error? I thought it would be something I was doing wrong. Also, I fixed it, I downgraded to 2017.2.0f3, and I don't get it anymore.

 

Huh..? For Unity devs to be aware of it.