https://fogbugz.unity3d.com/f/cases/edit/1310154/

NullReferenceException is thrown on trying to record an animation clip if Animation GameObject is not assigned under Capture dropdown. Refer the attached video

Steps to reproduce:
1) Create a new project
2) Window > Package Manager > Install Unity Recorder
3) Window > General > Recorder Window
4) Add Recorder > Animation clip > Start recording

Actual result: Recording fails with a NullReferenceException thrown in console
Expected result: No exceptions should be thrown in console

Occurring in: 2021.2.0a3, 2021.1.0b5, 2021.1.0a1, 2020.2.2f1, 2020.1.13f1, 2019.4.9f1

Environment: Both Windows and Mac

Stack trace:
NullReferenceException: srcGO
UnityEditor.Recorder.Input.AnimationInput.BeginRecording (UnityEditor.Recorder.RecordingSession session) (at Library/PackageCache/com.unity.recorder@2.5.2/Editor/Sources/Recorders/_Inputs/Animation/AnimationInput.cs:34)
UnityEditor.Recorder.Recorder.SignalInputsOfStage (UnityEditor.Recorder.ERecordingSessionStage stage, UnityEditor.Recorder.RecordingSession session) (at Library/PackageCache/com.unity.recorder@2.5.2/Editor/Sources/Recorder.cs:196)
UnityEditor.Recorder.RecordingSession.BeginRecording () (at Library/PackageCache/com.unity.recorder@2.5.2/Editor/Sources/RecordingSession.cs:112)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)