diff --git a/examples/react/src/App/routes.ts b/examples/react/src/App/routes.ts
index cb184b4a..2256ce52 100644
--- a/examples/react/src/App/routes.ts
+++ b/examples/react/src/App/routes.ts
@@ -1,5 +1,6 @@
 import Basic from '../examples/Basic';
 import Backgrounds from '../examples/Backgrounds';
+import BrokenNodes from '../examples/BrokenNodes';
 import ColorMode from '../examples/ColorMode';
 import ClickDistance from '../examples/ClickDistance';
 import ControlledUncontrolled from '../examples/ControlledUncontrolled';
@@ -77,6 +78,11 @@ const routes: IRoute[] = [
     path: 'backgrounds',
     component: Backgrounds,
   },
+  {
+    name: 'Broken Nodes',
+    path: 'broken-nodes',
+    component: BrokenNodes,
+  },
   {
     name: 'Color Mode',
     path: 'color-mode',
diff --git a/examples/react/src/examples/BrokenNodes/index.tsx b/examples/react/src/examples/BrokenNodes/index.tsx
new file mode 100644
index 00000000..990612f9
--- /dev/null
+++ b/examples/react/src/examples/BrokenNodes/index.tsx
@@ -0,0 +1,80 @@
+import { useCallback, useState } from 'react';
+import { ReactFlow, addEdge, Node, Connection, Edge, OnNodeDrag } from '@xyflow/react';
+
+const nodesInit: Node[] = [
+  {
+    id: '1a',
+    type: 'input',
+    data: { label: 'Node 1' },
+    position: { x: 250, y: 5 },
+    className: 'light',
+    ariaLabel: 'Input Node 1',
+  },
+  {
+    id: '2a',
+    data: { label: 'Node 2' },
+    position: { x: 100, y: 100 },
+    className: 'light',
+    ariaLabel: 'Default Node 2',
+  },
+  {
+    id: '3a',
+    data: { label: 'Node 3' },
+    position: { x: 400, y: 100 },
+    className: 'light',
+  },
+  {
+    id: '4a',
+    data: { label: 'Node 4' },
+    position: { x: 400, y: 200 },
+    className: 'light',
+  },
+];
+
+const edgesInit: Edge[] = [
+  { id: 'e1-2', source: '1a', target: '2a', ariaLabel: undefined },
+  { id: 'e1-3', source: '1a', target: '3a' },
+];
+
+const onNodesChange = () => {};
+const onEdgesChange = () => {};
+const BasicFlow = () => {
+  const [nodes, setNodes] = useState(nodesInit);
+  const [edges, setEdges] = useState(edgesInit);
+
+  const onConnect = useCallback((params: Connection | Edge) => setEdges((eds) => addEdge(params, eds)), [setEdges]);
+
+  const onNodeDrag: OnNodeDrag = useCallback((e, node) => {
+    if (isNaN(node.position.x) || isNaN(node.position.y)) {
+      console.log('received NaN', node.position);
+    }
+
+    setNodes((nds) => {
+      return nds.map((item) => {
+        if (item.id === node.id) {
+          return {
+            ...item,
+            position: {
+              x: node.position.x,
+              y: node.position.y,
+            },
+          };
+        }
+        return item;
+      });
+    });
+  }, []);
+
+  return (
+    <ReactFlow
+      nodes={nodes}
+      edges={edges}
+      onNodesChange={onNodesChange}
+      onEdgesChange={onEdgesChange}
+      onConnect={onConnect}
+      onNodeDrag={onNodeDrag}
+    ></ReactFlow>
+  );
+};
+
+export default BasicFlow;
diff --git a/packages/react/src/additional-components/NodeResizer/NodeResizeControl.tsx b/packages/react/src/additional-components/NodeResizer/NodeResizeControl.tsx
index 8a2faea7..5be4eafd 100644
--- a/packages/react/src/additional-components/NodeResizer/NodeResizeControl.tsx
+++ b/packages/react/src/additional-components/NodeResizer/NodeResizeControl.tsx
@@ -74,8 +74,8 @@ function ResizeControl({
 
           if (node && node.expandParent && node.parentId) {
             const origin = node.origin ?? nodeOrigin;
-            const width = change.width ?? node.measured.width!;
-            const height = change.height ?? node.measured.height!;
+            const width = change.width ?? node.measured.width ?? 0;
+            const height = change.height ?? node.measured.height ?? 0;
 
             const child: ParentExpandChild = {
               id: node.id,
diff --git a/packages/react/src/store/index.ts b/packages/react/src/store/index.ts
index 2d0552c0..5711102b 100644
--- a/packages/react/src/store/index.ts
+++ b/packages/react/src/store/index.ts
@@ -51,7 +51,7 @@ const createStore = ({
          * setNodes() is called exclusively in response to user actions:
          * - either when the `<ReactFlow nodes>` prop is updated in the controlled ReactFlow setup,
          * - or when the user calls something like `reactFlowInstance.setNodes()` in an uncontrolled ReactFlow setup.
-         * 
+         *
          * When this happens, we take the note objects passed by the user and extend them with fields
          * relevant for internal React Flow operations.
          */
@@ -161,9 +161,9 @@ const createStore = ({
             type: 'position',
             position: expandParent
               ? {
-                x: Math.max(0, dragItem.position.x),
-                y: Math.max(0, dragItem.position.y),
-              }
+                  x: Math.max(0, dragItem.position.x),
+                  y: Math.max(0, dragItem.position.y),
+                }
               : dragItem.position,
             dragging,
           };
@@ -174,8 +174,8 @@ const createStore = ({
               parentId: dragItem.parentId!,
               rect: {
                 ...dragItem.internals.positionAbsolute,
-                width: dragItem.measured.width!,
-                height: dragItem.measured.height!,
+                width: dragItem.measured.width ?? 0,
+                height: dragItem.measured.height ?? 0,
               },
             });
           }
diff --git a/packages/system/src/constants.ts b/packages/system/src/constants.ts
index 921189fa..9bb65656 100644
--- a/packages/system/src/constants.ts
+++ b/packages/system/src/constants.ts
@@ -26,6 +26,8 @@ export const errorMessages = {
     `It seems that you haven't loaded the styles. Please import '@xyflow/${lib}/dist/style.css' or base.css to make sure everything is working properly.`,
   error014: () =>
     'useNodeConnections: No node ID found. Call useNodeConnections inside a custom Node or provide a node ID.',
+  error015: () =>
+    'It seems that you are trying to drag a node that is not initialized. Please use onNodesChange as explained in the docs.',
 };
 
 export const infiniteExtent: CoordinateExtent = [
diff --git a/packages/system/src/utils/graph.ts b/packages/system/src/utils/graph.ts
index b2b1e6e5..9720e8c5 100644
--- a/packages/system/src/utils/graph.ts
+++ b/packages/system/src/utils/graph.ts
@@ -428,10 +428,14 @@ export function calculateNodePosition<NodeType extends NodeBase>({
     ? clampPosition(nextPosition, extent, node.measured)
     : nextPosition;
 
+  if (node.measured.width === undefined || node.measured.height === undefined) {
+    onError?.('015', errorMessages['error015']());
+  }
+
   return {
     position: {
-      x: positionAbsolute.x - parentX + node.measured.width! * origin[0],
-      y: positionAbsolute.y - parentY + node.measured.height! * origin[1],
+      x: positionAbsolute.x - parentX + (node.measured.width ?? 0) * origin[0],
+      y: positionAbsolute.y - parentY + (node.measured.height ?? 0) * origin[1],
     },
     positionAbsolute,
   };