diff --git a/extensions/ipynb/notebook-src/cellAttachmentRenderer.ts b/extensions/ipynb/notebook-src/cellAttachmentRenderer.ts
index 122c8267036..5ae4c13fcb6 100644
--- a/extensions/ipynb/notebook-src/cellAttachmentRenderer.ts
+++ b/extensions/ipynb/notebook-src/cellAttachmentRenderer.ts
@@ -22,7 +22,7 @@ export async function activate(ctx: RendererContext<void>) {
 		md.renderer.rules.image = (tokens: MarkdownItToken[], idx: number, options, env, self) => {
 			const token = tokens[idx];
 			const src = token.attrGet('src');
-			const attachments: Record<string, Record<string, string>> = env.outputItem.metadata.attachments;
+			const attachments: Record<string, Record<string, string>> | undefined = env.outputItem.metadata?.attachments;
 			if (attachments && src) {
 				const imageAttachment = attachments[src.replace('attachment:', '')];
 				if (imageAttachment) {