diff --git a/perl-xCAT/xCAT/SINV.pm b/perl-xCAT/xCAT/SINV.pm
index 23e64744d..76e3f19dd 100644
--- a/perl-xCAT/xCAT/SINV.pm
+++ b/perl-xCAT/xCAT/SINV.pm
@@ -835,6 +835,10 @@ sub compareoutput
                 {                                #  Host header
                     next;
                 }
+                if ($templateline =~ /UNKNOWN/)
+                {                                #  skip UNKNOWN header
+                    next;
+                }
                 if ($skiphostline == 1)
                 {
                     $skiphostline = 0;
@@ -1035,6 +1039,10 @@ sub diffoutput
                 {                                #  Host header
                     next;
                 }
+                if ($templateline =~ /UNKNOWN/)
+                {                                # skip UNKNOWN HEADER 
+                    next;
+                }
                 if ($skiphostline == 1)
                 {
                     $skiphostline = 0;