diff --git a/src/dehb/optimizers/dehb.py b/src/dehb/optimizers/dehb.py
index 9968518..f116942 100644
--- a/src/dehb/optimizers/dehb.py
+++ b/src/dehb/optimizers/dehb.py
@@ -269,6 +269,7 @@ def __getstate__(self):
         d = dict(self.__dict__)
         d["client"] = None  # hack to allow Dask client to be a class attribute
         d["logger"] = None  # hack to allow logger object to be a class attribute
+        d["_runtime_budget_timer"] = None # hack to allow timer object to be a class attribute
         return d
 
     def __del__(self):