diff --git a/C4/Members.pm b/C4/Members.pm
index 3e37aa4214..cf7ea7cc22 100644
--- a/C4/Members.pm
+++ b/C4/Members.pm
@@ -494,6 +494,7 @@ sub AddMember {
     $data{'dateofbirth'}     = undef if ( not $data{'dateofbirth'} );
     $data{'debarred'}        = undef if ( not $data{'debarred'} );
     $data{'sms_provider_id'} = undef if ( not $data{'sms_provider_id'} );
+    $data{'guarantorid'}     = undef if ( not $data{'guarantorid'} );
 
     # get only the columns of Borrower
     # FIXME Do we really need this check?