diff --git a/perl-xCAT/xCAT/CFMUtils.pm b/perl-xCAT/xCAT/CFMUtils.pm
index 314d3c4b9..2c66e0004 100644
--- a/perl-xCAT/xCAT/CFMUtils.pm
+++ b/perl-xCAT/xCAT/CFMUtils.pm
@@ -715,7 +715,7 @@ sub getPreBaseOSpkgsList {
         }
     }
     
-    @pre_selected = keys %pre_selected_hash;
+    my @pre_selected = keys %pre_selected_hash;
 
     return \@pre_selected;
 }