diff --git a/mycaldav/models.py b/mycaldav/models.py
index dfaf59e..0a3b50e 100644
--- a/mycaldav/models.py
+++ b/mycaldav/models.py
@@ -25,7 +25,7 @@ Key_separator = "--"
 
 
 class caldav_sync_manager(models.Model):    
-    dtDate = models.DateField('Date_synchronized', auto_now_add=True, unique=True)
+    dtDate = models.DateField('Date_synchronized', unique=True)
     bDone = models.BooleanField("Effectuée", default=False)
     dtUpdated = models.DateTimeField('date updated', auto_now=True)
     dtCreated = models.DateTimeField('date published', auto_now_add=True)