diff --git a/front_end/entrypoints/heap_snapshot_worker/HeapSnapshotLoader.ts b/front_end/entrypoints/heap_snapshot_worker/HeapSnapshotLoader.ts
index 9df2099ef44..c74ed17433f 100644
--- a/front_end/entrypoints/heap_snapshot_worker/HeapSnapshotLoader.ts
+++ b/front_end/entrypoints/heap_snapshot_worker/HeapSnapshotLoader.ts
@@ -72,6 +72,8 @@ export class HeapSnapshotLoader {
   }
 
   async buildSnapshot(secondWorker: MessagePort): Promise<JSHeapSnapshot> {
+    await this.parsingComplete;
+
     this.#snapshot = this.#snapshot || {};
 
     this.#progress.updateStatus('Processing snapshot…');