diff --git a/toolkit.py b/toolkit.py
index ff47669b839462d85a813a47dc79771339e6b5be..65c526f3bc5a98df14ecbfd18e203cfabae0b00a 100755
--- a/toolkit.py
+++ b/toolkit.py
@@ -528,7 +528,7 @@ class ClassificationProject(object):
                     os.symlink(srcpath, filename)
                     logger.info("Created symlink from {} to {}".format(srcpath, filename))
             logger.info("Trying to load {} from {}".format(dataset_name, filename))
-            with h5py.File(filename) as hf:
+            with h5py.File(filename, "r") as hf:
                 setattr(self, dataset_name,  hf[dataset_name][:])
         logger.info("Data loaded")