[Solved]unexplanable null refrence exception

Questions & Answers
1

so i was working with animation for the first time today using it to animate part of a (4.5) UI. and at one point (really not sure when) i started getting this nullref error. it doesn’t seem to do anything…but its there and it worries me that it could be hurting something in the background. i have no scripts for this animation its 100% done with the editor (animation editor and the animation node editor)
heres the stack trace. maybe someone can help me figure out what’s causing it so i can put a stop to it

(p.s. : i completely removed the animation controller from the game object and this was still happening so i really don’t know right now why this is a thing)

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.Graphs.AnimationStateMachine.TransitionEditionContext.BuildNames () (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/AnimationStateMachine/TransitionEditionContext.cs:44)
UnityEditor.Graphs.AnimationStateMachine.TransitionEditionContext..ctor (UnityEditor.Animations.AnimatorTransitionBase aTransition, UnityEditor.Animations.AnimatorState aSourceState, UnityEditor.Animations.AnimatorStateMachine aSourceStateMachine, UnityEditor.Animations.AnimatorStateMachine aOwnerStateMachine) (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/AnimationStateMachine/TransitionEditionContext.cs:28)
UnityEditor.Graphs.AnimationStateMachine.AnimatorTransitionInspectorBase.ComputeTransitionContexts () (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/AnimationStateMachine/AnimatorTransitionInspectorBase.cs:125)
UnityEditor.Graphs.AnimationStateMachine.AnimatorTransitionInspectorBase.OnEnable () (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/AnimationStateMachine/AnimatorTransitionInspectorBase.cs:87)
UnityEditor.Graphs.AnimationStateMachine.AnimatorStateTransitionInspector.OnEnable () (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/AnimationStateMachine/AnimatorStateTransitionInspector.cs:58)
2

Had to restart unity! thanks to zach.r.d and Positive7 for the tip!!!

4

Yeah try restarting Unity. Sonewhat inexplicable null reference voids occur in 4.5. These do not persist after the game is compiled.

5

just save your current layout, it should solve your error,

3

I found my Animation Play, Pause and Next Frame buttons were Red suggesting the animation was still trying to record key frames.
Once I turned these off (by pressing the red play button again - the one that normally enters the play game mode) I was able to continue as before.