diff --git a/torch_sim/runners.py b/torch_sim/runners.py
index 91f5a340..81a5451f 100644
--- a/torch_sim/runners.py
+++ b/torch_sim/runners.py
@@ -406,7 +406,7 @@ def convergence_fn(
         """
         force_conv = ts.system_wise_max_force(state) < force_tol
 
-        if include_cell_forces:
+        if include_cell_forces and hasattr(state, "cell_forces"):
             if (cell_forces := getattr(state, "cell_forces", None)) is None:
                 raise ValueError("cell_forces not found in state")
             cell_forces_norm, _ = cell_forces.norm(dim=2).max(dim=1)