diff --git a/xCAT-server/lib/xcat/plugins/AAsn.pm b/xCAT-server/lib/xcat/plugins/AAsn.pm
index 5486a6c07..4145f7589 100644
--- a/xCAT-server/lib/xcat/plugins/AAsn.pm
+++ b/xCAT-server/lib/xcat/plugins/AAsn.pm
@@ -294,7 +294,7 @@ sub mountInstall
     my $nomount = 0;
 
     my $retdata = xCAT::Utils->readSNInfo($nodename);
-    if ($retdata->{'arch'})
+    if (ref $retdata and $retdata->{'arch'})
     {                               # no error
         $master = $retdata->{'master'};    # management node
         $os     = $retdata->{'os'};