diff --git a/addons/caldav/calendar.py b/addons/caldav/calendar.py
index 17ae2c91370..a45152501cc 100644
--- a/addons/caldav/calendar.py
+++ b/addons/caldav/calendar.py
@@ -228,7 +228,7 @@ class CalDAV(object):
 
         att_data = []
         for cal_data in child.getChildren():
-            if cal_data.name.lower() == 'organizer':           
+            if cal_data.name.lower() == 'organizer':
                 self.ical_set(cal_data.name.lower(), {'name':cal_data.params['CN']}, 'value')
             if cal_data.name.lower() == 'attendee':
                 ctx = context.copy()
@@ -268,7 +268,7 @@ class CalDAV(object):
         if not datas:
             return
         timezones = []
-        for data in datas:           
+        for data in datas:
             tzval = None
             vevent = ical.add(name)
             for field in self.__attribute__.keys():
@@ -423,7 +423,7 @@ class CalDAV(object):
         return res
 
 class Calendar(CalDAV, osv.osv):
-    _name = 'basic.calendar'    
+    _name = 'basic.calendar'
     _calname = 'calendar'
 
     __attribute__ = {
@@ -440,13 +440,13 @@ class Calendar(CalDAV, osv.osv):
         'vtimezone': None, # Use: O-n, Type: Collection of Timezone class
     }
     _columns = {
-            'name': fields.char("Name", size=64),            
+            'name': fields.char("Name", size=64),
             'user_id': fields.many2one('res.users', 'Owner'),
             'collection_id': fields.many2one('document.directory', 'Collection', \
                                            required=True),
             'type': fields.selection([('vevent', 'Event'), ('vtodo', 'TODO')], \
                                     string="Type", size=64),
-            'line_ids': fields.one2many('basic.calendar.lines', 'calendar_id', 'Calendar Lines'),            
+            'line_ids': fields.one2many('basic.calendar.lines', 'calendar_id', 'Calendar Lines'),
             'create_date': fields.datetime('Created Date'),
             'write_date': fields.datetime('Modifided Date'),
     }
@@ -457,8 +457,8 @@ class Calendar(CalDAV, osv.osv):
         if not domain:
             domain = []
         res = []
-        ctx_res_id = context.get('res_id', None) 
-        ctx_model = context.get('model', None)  
+        ctx_res_id = context.get('res_id', None)
+        ctx_model = context.get('model', None)
         for cal in self.browse(cr, uid, ids):
             for line in cal.line_ids:
                 if ctx_model and ctx_model != line.object_id.model:
@@ -467,13 +467,13 @@ class Calendar(CalDAV, osv.osv):
                     continue
                 line_domain = eval(line.domain)
                 line_domain += domain
-                if ctx_res_id:                    
+                if ctx_res_id:
                     line_domain += [('id','=',ctx_res_id)]
                 mod_obj = self.pool.get(line.object_id.model)
-                data_ids = mod_obj.search(cr, uid, line_domain, context=context) 
+                data_ids = mod_obj.search(cr, uid, line_domain, context=context)
                 for data in mod_obj.browse(cr, uid, data_ids, context):
                     ctx = parent and parent.context or None
-                    node = res_node_calendar('%s' %data.id, parent, ctx, data, line.object_id.model, data.id)                                   
+                    node = res_node_calendar('%s' %data.id, parent, ctx, data, line.object_id.model, data.id)
                     res.append(node)
         return res
 
@@ -487,8 +487,8 @@ class Calendar(CalDAV, osv.osv):
         """
         if not context:
            context = {}
-        ctx_model = context.get('model', None)            
-        ctx_res_id = context.get('res_id', None)  
+        ctx_model = context.get('model', None)
+        ctx_res_id = context.get('res_id', None)
         ical = vobject.iCalendar()
         for cal in self.browse(cr, uid, ids):
             for line in cal.line_ids:
@@ -497,7 +497,7 @@ class Calendar(CalDAV, osv.osv):
                 if line.name in ('valarm', 'attendee'):
                     continue
                 domain = eval(line.domain)
-                if ctx_res_id:                    
+                if ctx_res_id:
                     domain += [('id','=',ctx_res_id)]
                 mod_obj = self.pool.get(line.object_id.model)
                 data_ids = mod_obj.search(cr, uid, domain, context=context)
@@ -505,7 +505,7 @@ class Calendar(CalDAV, osv.osv):
                 context.update({'model': line.object_id.model,
                                         'calendar_id': cal.id
                                         })
-                self.__attribute__ = get_attribute_mapping(cr, uid, line.name, context)            
+                self.__attribute__ = get_attribute_mapping(cr, uid, line.name, context)
                 self.create_ics(cr, uid, datas, line.name, ical, context=context)
         return ical.serialize()
 
@@ -520,16 +520,18 @@ class Calendar(CalDAV, osv.osv):
 
         if not context:
             context = {}
-        vals = []        
+        vals = []
         ical_data = base64.decodestring(content)
         parsedCal = vobject.readOne(ical_data)
         if not data_id:
-            data_id = self.search(cr, uid, [])[0]  
+            data_id = self.search(cr, uid, [])[0]
         cal = self.browse(cr, uid, data_id, context=context)
         cal_children = {}
         count = 0
         for line in cal.line_ids:
             cal_children[line.name] = line.object_id.model
+        objs = []
+        checked = True
         for child in parsedCal.getChildren():
             if child.name.lower() in cal_children:
                 context.update({'model': cal_children[child.name.lower()],
@@ -538,10 +540,13 @@ class Calendar(CalDAV, osv.osv):
                 self.__attribute__ = get_attribute_mapping(cr, uid, child.name.lower(), context=context)
                 val = self.parse_ics(cr, uid, child, cal_children=cal_children, context=context)
                 vals.append(val)
-                obj = self.pool.get(cal_children[child.name.lower()])
-        if hasattr(obj, 'check_import'):
-            obj.check_import(cr, uid, vals, context=context)
-        else:
+                objs.append(cal_children[child.name.lower()])
+        for obj_name in list(set(objs)):
+            obj = self.pool.get(obj_name)
+            if hasattr(obj, 'check_import'):
+                obj.check_import(cr, uid, vals, context=context)
+                checked = True
+        if not checked:
             self.check_import(cr, uid, vals, context=context)
         return {}
 Calendar()