stride3d/stride · error · InvalidOperationException

The folder being deleted is not empty.

Error message

The folder being deleted is not empty.

What it means

EntityFolderViewModel.Delete() refuses to delete a folder that still contains entities (directly or in subfolders, via InnerSubEntities). Stride requires folders to be emptied first so the undo/redo operation only has to record a simple folder deletion. Thrown as InvalidOperationException before any hierarchy mutation happens.

Solutions

1. Move or delete all entities inside the folder (and subfolders) before calling Delete()
2. Check InnerSubEntities.Any() before calling Delete and inform the user the folder must be empty
3. Recursively delete subfolders after emptying them, then delete the parent folder

Example fix

// before
folder.Delete(); // throws if not empty
// after
if (!folder.InnerSubEntities.Any())
    folder.Delete();
else
    // move/delete entities first or notify the user

if (folder.InnerSubEntities.Any()) throw new InvalidOperationException("Move or delete entities before deleting this folder.");
folder.Delete();

try { folder.Delete(); }
catch (InvalidOperationException) { /* prompt user to empty the folder */ }

When it happens

Trigger: Calling Delete() on an EntityFolderViewModel whose InnerSubEntities collection is non-empty, e.g. deleting a folder that has entities placed in it or in any nested subfolder.

Common situations: User-facing 'delete folder' command invoked on a populated folder; scripted batch cleanup of an entity hierarchy that forgot to move or delete child entities first.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

• MicroThread was already started before.
• The entity to insert has already been destroyed
• Cannot change the name of a EntityHierarchyRootViewModel…
• and cannot both be empty.
• There must be two and only two input values for Int2.

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/9dddd662aa1e31fa. Report an issue: GitHub.

Appendix: source

Thrown at sources/editor/Stride.Assets.Presentation/AssetEditors/EntityHierarchyEditor/ViewModels/EntityFolderViewModel.cs:132

            var indexInFolder = 0;
            var i = 0;
            foreach (var entity in entityCollection)
            {
                if (i++ == indexInEntity)
                    break;

                if (string.Equals(entity.Folder, Path, FolderCase))
                    ++indexInFolder;
            }
            return indexInFolder;
        }

        /// <summary>
        /// Deletes this folder. The folder must not contain any entity before being deleted.
        /// </summary>
        public void Delete()
        {
            if (InnerSubEntities.Any()) throw new InvalidOperationException("The folder being deleted is not empty.");
            var path = Path;
            var ownerId = Owner.Id;
            if (Parent == null) throw new InvalidOperationException($"{nameof(Parent)} cannot be null");
            Parent.Folders.Remove(this);
            if (!Editor.UndoRedoService.UndoRedoInProgress)
            {
                var operation = new EntityFolderOperation(Asset, EntityFolderOperation.Action.FolderDeleted, path, ownerId);
                Editor.UndoRedoService.PushOperation(operation);
            }
        }

        /// <inheritdoc />
        public override GraphNodePath GetNodePath()
        {
            return Owner.GetNodePath();
        }

        private bool CanUpdateName([CanBeNull] string newName)

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