fix #51188

src/vs/workbench/common/editor.ts

@@ -1063,14 +1063,16 @@ export class EditorViewStateMemento<T> {
 	public loadState(group: IEditorGroup, editor: EditorInput): T;
 	public loadState(group: IEditorGroup, resourceOrEditor: URI | EditorInput): T {
 		const resource = this.doGetResource(resourceOrEditor);
-		if (resource) {
+		if (!resource || !group) {
+			return void 0; // we are not in a good state to load any viewstate for a resource
+		}
+
 		const cache = this.doLoad();
 
 		const viewStates = cache.get(resource.toString());
 		if (viewStates) {
 			return viewStates[group.id];
 		}
-		}
 
 		return void 0;
 	}