diff --git a/agkyra/agkyra/syncer/syncer.py b/agkyra/agkyra/syncer/syncer.py
index d032c54b5c75c83a7708a0e6800cf8262c860e34..131dd67b610a5daffef452aaf20561d211c3b8c7 100644
--- a/agkyra/agkyra/syncer/syncer.py
+++ b/agkyra/agkyra/syncer/syncer.py
@@ -284,8 +284,8 @@ class FileSyncer(object):
         db = self.get_db()
         if archives is None:
             archives = (self.MASTER, self.SLAVE)
-        return list(db.list_deciding(archives=archives,
-                                     sync=self.SYNC))
+        return set(db.list_deciding(archives=archives,
+                                    sync=self.SYNC))
 
     def probe_archive(self, archive):
         client = self.clients[archive]