diff --git a/swh/vault/api/client.py b/swh/vault/api/client.py
index 1cbe705..db63db9 100644
--- a/swh/vault/api/client.py
+++ b/swh/vault/api/client.py
@@ -1,54 +1,60 @@
 # Copyright (C) 2016-2017  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 from swh.model import hashutil
 from swh.core.api import SWHRemoteAPI
-from swh.storage.exc import StorageAPIError
+
+
+class VaultAPIError(Exception):
+    """Vault API Error"""
+    def __str__(self):
+        return ('An unexpected error occurred in the Vault backend: {}'
+                .format(self.args))
 
 
 class RemoteVaultClient(SWHRemoteAPI):
     """Client to the Software Heritage vault cache."""
 
     def __init__(self, base_url):
-        super().__init__(api_exception=StorageAPIError, url=base_url)
+        super().__init__(api_exception=VaultAPIError, url=base_url)
 
     # Web API endpoints
 
     def fetch(self, obj_type, obj_id):
         hex_id = hashutil.hash_to_hex(obj_id)
         return self.get('fetch/{}/{}'.format(obj_type, hex_id))
 
     def cook(self, obj_type, obj_id, email=None):
         hex_id = hashutil.hash_to_hex(obj_id)
         return self.post('cook/{}/{}'.format(obj_type, hex_id),
                          data={},
                          params=({'email': email} if email else None))
 
     def progress(self, obj_type, obj_id):
         hex_id = hashutil.hash_to_hex(obj_id)
         return self.get('progress/{}/{}'.format(obj_type, hex_id))
 
     # Cookers endpoints
 
     def set_progress(self, obj_type, obj_id, progress):
         hex_id = hashutil.hash_to_hex(obj_id)
         return self.post('set_progress/{}/{}'.format(obj_type, hex_id),
                          data=progress)
 
     def set_status(self, obj_type, obj_id, status):
         hex_id = hashutil.hash_to_hex(obj_id)
         return self.post('set_status/{}/{}' .format(obj_type, hex_id),
                          data=status)
 
     # TODO: handle streaming properly
     def put_bundle(self, obj_type, obj_id, bundle):
         hex_id = hashutil.hash_to_hex(obj_id)
         return self.post('put_bundle/{}/{}' .format(obj_type, hex_id),
                          data=bundle)
 
     def send_notif(self, obj_type, obj_id):
         hex_id = hashutil.hash_to_hex(obj_id)
         return self.post('send_notif/{}/{}' .format(obj_type, hex_id),
                          data=None)