diff --git a/aquamarine-vm/src/aquamarine_stepper_vm.rs b/aquamarine-vm/src/aquamarine_stepper_vm.rs
index b4e2902e..31e57f26 100644
--- a/aquamarine-vm/src/aquamarine_stepper_vm.rs
+++ b/aquamarine-vm/src/aquamarine_stepper_vm.rs
@@ -73,7 +73,7 @@ impl AquamarineVM {
 
         let prev_data_path = self.particle_data_store.join(particle_id);
         // TODO: check for errors related to invalid file content (such as invalid UTF8 string)
-        let prev_data = std::fs::read_to_string(&prev_data_path).unwrap_or(String::from("{}"));
+        let prev_data = std::fs::read_to_string(&prev_data_path).unwrap_or(String::from("[]"));
         let args = vec![
             IValue::String(init_user_id.into()),
             IValue::String(aqua.into()),