Steps to reproduce:
1. Create new Unity project using empty URP 3D Template
2. In Hierarchy window right-click in SampleScene
3. Select “Add New Scene”
4. Save the Scene/project
5. Right-click on newly created Scene in Inspector window
6. Select “Unload Scene”
7. Right-click again
8. Select Prefab > Remove Unused Overrides
9. Observe the Console window

Actual results: warning is thrown “ArgumentException: The scene is not loaded.”

Expected results: user should not be able to select to Remove Unused Overrides in not loaded Scene

Reproducible with versions: 6000.0.60f1, 6000.2.8f1, 6000.3.0b6, 6000.4.0a2

Tested on (OS): macOS Silicon, Tahoe 26.0 (M1)

Error:
ArgumentException: The scene is not loaded.
UnityEngine.SceneManagement.Scene.GetRootGameObjects (System.Collections.Generic.List`1[T] rootGameObjects) (at /Users/bokken/build/output/unity/unity/Runtime/Export/SceneManager/Scene.cs:106)
UnityEngine.SceneManagement.Scene.GetRootGameObjects () (at /Users/bokken/build/output/unity/unity/Runtime/Export/SceneManager/Scene.cs:90)
UnityEditor.PrefabUtility.GetScenePrefabInstancesWithNonDefaultOverrides (UnityEngine.SceneManagement.Scene scene) (at /Users/bokken/build/output/unity/unity/Editor/Mono/Prefabs/PrefabUtility.cs:415)
UnityEditor.PrefabUtility.RemoveAllPrefabInstancesUnusedOverridesFromScene (UnityEngine.SceneManagement.Scene scene) (at /Users/bokken/build/output/unity/unity/Editor/Mono/Prefabs/PrefabUtility.cs:403)
UnityEditor.PrefabUtility.RemoveAllPrefabInstancesUnusedOverridesFromSceneForMenuItem (System.Object userData) (at /Users/bokken/build/output/unity/unity/Editor/Mono/Prefabs/PrefabUtility.cs:393)
Unity.Hierarchy.Editor.HierarchySceneHandler.RemoveAllPrefabInstancesUnusedOverridesFromSceneForMenuItem (UnityEngine.UIElements.DropdownMenuAction obj) (at /Users/bokken/build/output/unity/unity/Modules/HierarchyEditor/ScriptBindings/HierarchySceneHandler.bindings.cs:306)
UnityEngine.UIElements.DropdownMenuAction.Execute () (at /Users/bokken/build/output/unity/unity/Modules/UIElements/Core/DropdownMenu.cs:224)
UnityEditor.UIElements.EditorMenuExtensions+<>c__DisplayClass0_0.<PrepareMenu>b__0 () (at /Users/bokken/build/output/unity/unity/Editor/Mono/UIElements/EditorMenuExtensions.cs:36)
UnityEditor.GenericMenu.CatchMenu (System.Object userData, System.String[] options, System.Int32 selected) (at /Users/bokken/build/output/unity/unity/Editor/Mono/GUI/GenericMenu.cs:162)