UnassignedReferenceException Error Not Going Away!

This is the exact error:

UnassignedReferenceException: The variable m_AnimatorController of AnimatorControllerTool has not been assigned.
You probably need to assign the m_AnimatorController variable of the AnimatorControllerTool script in the inspector.
UnityEditor.Graphs.AnimationStateMachine.TransitionInspector.OnEnable () (at C:/BuildAgent/work/d63dfc6385190b60/Editor/Graphs/UnityEditor.Graphs/AnimationStateMachine/TransitionInspector.cs:77)

I don’t quite understand why this error happens because I don’t use Animator in my game, I may have spawned an animator object or something before, but How can I get rid of this error??? Am I taking up memory leaving it here??

Somewhere in your scene there is an object with a script called AnimatorControllerTool. The script is trying to access a public variable that you have not set in the inspector.

So I have also run into this error and there is not an AnimatorControllerTool in the scene. I suspect this error involves the Unity Engines Animator component code.