diff --git a/src/renderer/renderer.ts b/src/renderer/renderer.ts
index ca8ac956..95178f93 100644
--- a/src/renderer/renderer.ts
+++ b/src/renderer/renderer.ts
@@ -991,7 +991,8 @@ export class SDFGRenderer extends EventEmitter {
         this.sdfg_tree = {};
         this.for_all_sdfg_elements(
             (otype: SDFGElementGroup, odict: any, obj: any) => {
-                if (obj.type === SDFGElementType.NestedSDFG)
+                if (obj.type === SDFGElementType.NestedSDFG &&
+                    obj.attributes.sdfg)
                     this.sdfg_tree[obj.attributes.sdfg.sdfg_list_id] =
                         odict.sdfg.sdfg_list_id;
             }
@@ -1907,7 +1908,8 @@ export class SDFGRenderer extends EventEmitter {
 
                                 // If nested SDFG, traverse recursively
                                 if (node.data.node.type ===
-                                    SDFGElementType.NestedSDFG)
+                                    SDFGElementType.NestedSDFG &&
+                                    node.attributes().sdfg)
                                     traverseRecursive(
                                         node.data.graph,
                                         node.attributes().sdfg.attributes.name,
@@ -2004,7 +2006,8 @@ export class SDFGRenderer extends EventEmitter {
                     );
 
                     // If nested SDFG, traverse recursively
-                    if (node.type === SDFGElementType.NestedSDFG)
+                    if (node.type === SDFGElementType.NestedSDFG &&
+                        node.attributes.sdfg)
                         traverse_recursive(node.attributes.sdfg);
                 });
 
@@ -3739,7 +3742,7 @@ function relayoutSDFGState(
         const topleft = gnode.topleft();
 
         // Offset nested SDFG.
-        if (node.type === SDFGElementType.NestedSDFG) {
+        if (node.type === SDFGElementType.NestedSDFG && node.attributes.sdfg) {
 
             offset_sdfg(node.attributes.sdfg, gnode.data.graph, {
                 x: topleft.x + SDFV.LINEHEIGHT,
diff --git a/src/renderer/renderer_elements.ts b/src/renderer/renderer_elements.ts
index 44adbb7c..be2383fe 100644
--- a/src/renderer/renderer_elements.ts
+++ b/src/renderer/renderer_elements.ts
@@ -2087,7 +2087,9 @@ export class NestedSDFG extends SDFGNode {
             ctx.fillStyle = this.getCssProperty(
                 renderer, '--node-foreground-color'
             );
-            const label = this.data.node.attributes.label;
+            let label = this.data.node.attributes.label;
+            if (!this.data.node.attributes.sdfg)
+                label += ' (not loaded)';
             const textmetrics = ctx.measureText(label);
             ctx.fillText(
                 label, this.x - textmetrics.width / 2.0,
@@ -2514,7 +2516,8 @@ export function offset_state(
             c.y += offset.y;
         });
 
-        if (node.data.node.type === SDFGElementType.NestedSDFG)
+        if (node.data.node.type === SDFGElementType.NestedSDFG &&
+            node.data.node.attributes.sdfg)
             offset_sdfg(
                 node.data.node.attributes.sdfg, node.data.graph, offset
             );
diff --git a/src/sdfv.ts b/src/sdfv.ts
index bac3f2fe..a46099df 100644
--- a/src/sdfv.ts
+++ b/src/sdfv.ts
@@ -326,7 +326,7 @@ export class SDFV {
         }
 
         // If nested SDFG, add SDFG information too
-        if (elem instanceof NestedSDFG) {
+        if (elem instanceof NestedSDFG && elem.attributes().sdfg) {
             const sdfg_sdfg = elem.attributes().sdfg;
             contents.append($('<br>'));
             contents.append($('<h4>', {
diff --git a/src/utils/sdfg/traversal.ts b/src/utils/sdfg/traversal.ts
index 50e02b92..0fe45d37 100644
--- a/src/utils/sdfg/traversal.ts
+++ b/src/utils/sdfg/traversal.ts
@@ -279,7 +279,7 @@ export function memlet_tree_nested(
                 const name = edge.dst_connector;
                 const nested_sdfg = next_node.attributes.sdfg;
 
-                nested_sdfg.nodes.forEach((nstate: any) => {
+                nested_sdfg?.nodes.forEach((nstate: any) => {
                     nstate.edges.forEach((e: any) => {
                         const node = nstate.nodes[e.src];
                         if (node.type === SDFGElementType.AccessNode &&
@@ -328,7 +328,7 @@ export function memlet_tree_nested(
                 const name = edge.src_connector;
                 const nested_sdfg = next_node.attributes.sdfg;
 
-                nested_sdfg.nodes.forEach((nstate: JsonSDFGState) => {
+                nested_sdfg?.nodes.forEach((nstate: JsonSDFGState) => {
                     nstate.edges.forEach((e: JsonSDFGEdge) => {
                         const node = nstate.nodes[parseInt(e.dst)];
                         if (node.type === SDFGElementType.AccessNode &&
@@ -394,7 +394,7 @@ export function memlet_tree_recursive(root_sdfg: JsonSDFG): any[] {
         });
 
         state.nodes.forEach((n: JsonSDFGNode) => {
-            if (n.type == SDFGElementType.NestedSDFG) {
+            if (n.type == SDFGElementType.NestedSDFG && n.attributes.sdfg) {
                 const t = memlet_tree_recursive(n.attributes.sdfg);
                 trees = trees.concat(t);
             }