diff --git a/api/dao/containerutil.py b/api/dao/containerutil.py
index 312b784b8a345f1b567cfb8181f6135a54430ca9..fe1d0580c30abd55325fb71268995f2f459801dc 100644
--- a/api/dao/containerutil.py
+++ b/api/dao/containerutil.py
@@ -2,7 +2,6 @@ import bson.objectid
 
 from .. import config
 from ..auth import INTEGER_ROLES
-from ..validators import InputValidationException
 
 CONT_TYPES = ['acquisition', 'analysis', 'collection', 'group', 'project', 'session']
 SINGULAR_TO_PLURAL = {
@@ -202,11 +201,11 @@ def pluralize(cont_name):
         return SINGULAR_TO_PLURAL[cont_name]
     elif cont_name in PLURAL_TO_SINGULAR:
         return cont_name
-    raise InputValidationException('Could not pluralize unknown container name {}'.format(cont_name))
+    raise ValueError('Could not pluralize unknown container name {}'.format(cont_name))
 
 def singularize(cont_name):
     if cont_name in PLURAL_TO_SINGULAR:
         return PLURAL_TO_SINGULAR[cont_name]
     elif cont_name in SINGULAR_TO_PLURAL:
         return cont_name
-    raise InputValidationException('Could not singularize unknown container name {}'.format(cont_name))
+    raise ValueError('Could not singularize unknown container name {}'.format(cont_name))
diff --git a/api/download.py b/api/download.py
index 5487c87ee412faad0953c177f78cc6ff3f65a95c..9259af1b3b111bb11dacd6737f895fb9401fc79e 100644
--- a/api/download.py
+++ b/api/download.py
@@ -86,12 +86,16 @@ class Download(base.RequestHandler):
         targets = []
 
         for fref in file_refs:
-            cont_name   = pluralize(fref.get('container_name',''))
+
             cont_id     = fref.get('container_id', '')
             filename    = fref.get('filename', '')
+            cont_name   = fref.get('container_name','')
 
-            if cont_name not in ['projects', 'sessions', 'acquisitions', 'analyses']:
+            if cont_name not in ['project', 'session', 'acquisition', 'analysis']:
                 self.abort(400, 'Bulk download only supports files in projects, sessions, analyses and acquisitions')
+            cont_name   = pluralize(fref.get('container_name',''))
+
+
             file_obj = None
             try:
                 # Try to find the file reference in the database (filtering on user permissions)