diff --git a/SoObjects/SOGo/SOGoSAML2Session.m b/SoObjects/SOGo/SOGoSAML2Session.m
index e9258d694..4cd4750e1 100644
--- a/SoObjects/SOGo/SOGoSAML2Session.m
+++ b/SoObjects/SOGo/SOGoSAML2Session.m
@@ -77,7 +77,7 @@ static NSMapTable *serverTable = nil;
 {
   if (!serverTable)
     {
-      serverTable = [NSMapTable mapTableWithStrongToWeakObjects];
+      serverTable = NSCreateMapTable(NSObjectMapKeyCallBacks, NSNonRetainedObjectMapValueCallBacks, 128);
       [serverTable retain];
     }
   lasso_init ();