diff --git a/mlair/data_handler/default_data_handler.py b/mlair/data_handler/default_data_handler.py
index 52835975101f5ce6881b72b127e16c0e299dfb14..e4367184830b94f910cf42ae7887585ba958009d 100644
--- a/mlair/data_handler/default_data_handler.py
+++ b/mlair/data_handler/default_data_handler.py
@@ -13,6 +13,7 @@ from functools import reduce
 from typing import Tuple, Union, List
 import multiprocessing
 import psutil
+import dask
 
 import numpy as np
 import xarray as xr
@@ -84,7 +85,7 @@ class DefaultDataHandler(AbstractDataHandler):
             self._cleanup() if fresh_store is True else None
             data = {"X": self._X, "Y": self._Y, "X_extreme": self._X_extreme, "Y_extreme": self._Y_extreme}
             with open(self._save_file, "wb") as f:
-                pickle.dump(data, f)
+                pickle.dump(dask.compute(data), f)
             logging.debug(f"save pickle data to {self._save_file}")
             self._reset_data()