diff --git a/baseprocessor.py b/baseprocessor.py
index 85d61e1..c70b213 100644
--- a/baseprocessor.py
+++ b/baseprocessor.py
@@ -9,8 +9,9 @@ from functools import partial
 import numpy as np
 
 import tables
-
 from tables import HDF5ExtError
+from tables.registry import class_name_dict
+
 from params import default_params, load_params
 from units import U
 import traceback
@@ -408,8 +409,14 @@ class HDF5Container(BaseProcessor):
             except TypeError:
                 data = np.array([data])
 
+            group_name =  os.path.dirname(name_full)
+            if group_name in self.save:
+                group = self.save[group_name]
+                if not isinstance(group, class_name_dict['Group']):
+                    self._log(f"{group_name} already there and no a group, deleting", "WARNING")
+                    self.save.remove_node(group)
             self.save.create_array(
-                os.path.dirname(name_full),
+                group_name,
                 os.path.basename(name_full),
                 data,
                 description,
diff --git a/snapshotprocessor.py b/snapshotprocessor.py
index 4d061d1..49584eb 100644
--- a/snapshotprocessor.py
+++ b/snapshotprocessor.py
@@ -489,6 +489,8 @@ class SnapshotProcessor(HDF5Container):
         self.open()
         if "/maps" not in self.save:
             self.save.create_group("/", "maps", "2D maps")
+        if "/hist" not in self.save:
+            self.save.create_group("/", "hist", "Histograms")
         if "/datasets" not in self.save:
             self.save.create_group("/", "datasets", "Complex datasets")
         self.save.root.maps._v_attrs.center = center