Steps to reproduce:

1. Open the attached project

1. Observe that the Project window is locked

1. Close the project

1. Create a new project (URP 3D Template was used for testing)

1. Observe the Console window after the new project launches

Actual results: NullReferenceExceptions are spammed in the console until the Project window is unlocked

Expected results: No errors are thrown or a clear explanation is given to the user that the Project window should be unlocked

Reproducible with versions: 2022.3.60f1, 6000.0.43f1, 6000.1.0b11, 6000.2.0a7

Tested on (OS): mac OS 15.3.2

Full error messages:

• {{{}NullReferenceException: Object reference not set to an instance of an object{}}}{{{}UnityEditor.ObjectListArea+LocalGroup.UpdateAssets () (at /Users/bokken/build/output/unity/unity/Editor/Mono/ObjectListLocalGroup.cs:135){}}}{{{}UnityEditor.ObjectListArea.SetupData (System.Boolean forceReflow) (at /Users/bokken/build/output/unity/unity/Editor/Mono/ObjectListArea.cs:1021){}}}{{{}UnityEditor.ObjectListArea.HandleListArea () (at /Users/bokken/build/output/unity/unity/Editor/Mono/ObjectListArea.cs:1039){}}}{{{}UnityEditor.ObjectListArea.OnGUI (UnityEngine.Rect position, System.Int32 keyboardControlID) (at /Users/bokken/build/output/unity/unity/Editor/Mono/ObjectListArea.cs:391){}}}{{{}UnityEditor.ProjectBrowser.OnGUI () (at /Users/bokken/build/output/unity/unity/Editor/Mono/ProjectBrowser/ProjectBrowser.cs:2059){}}}{{{}UnityEditor.HostView.InvokeOnGUI (UnityEngine.Rect onGUIPosition) (at /Users/bokken/build/output/unity/unity/Editor/Mono/HostView.cs:518){}}}{{{}UnityEditor.DockArea.DrawView (UnityEngine.Rect dockAreaRect) (at /Users/bokken/build/output/unity/unity/Editor/Mono/GUI/DockArea.cs:399){}}}{{{}UnityEditor.DockArea.OldOnGUI () (at /Users/bokken/build/output/unity/unity/Editor/Mono/GUI/DockArea.cs:390){}}}{{{}UnityEngine.UIElements.IMGUIContainer.DoOnGUI (UnityEngine.Event evt, UnityEngine.Matrix4x4 parentTransform, UnityEngine.Rect clippingRect, System.Boolean isComputingLayout, UnityEngine.Rect layoutSize, System.Action onGUIHandler, System.Boolean canAffectFocus) (at /Users/bokken/build/output/unity/unity/Modules/UIElements/Core/IMGUIContainer.cs:403){}}}{{{}UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&) (at /Users/bokken/build/output/unity/unity/Modules/IMGUI/GUIUtility.cs:219){}}}

• {{GUI Error: You are pushing more GUIClips than you are popping. Make sure they are balanced.UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&) (at /Users/bokken/build/output/unity/unity/Modules/IMGUI/GUIUtility.cs:219)}}