diff --git a/@msh/private/writefort15.m b/@msh/private/writefort15.m
index 9014d248..0d536df8 100644
--- a/@msh/private/writefort15.m
+++ b/@msh/private/writefort15.m
@@ -158,8 +158,10 @@
 ibtype = [2 12 22 32 52] ;
 sm = 0 ;
 
-for k = 1: length(ibtype)
-    sm = sm + sum(~(boudat.ibtype - ibtype(k))) ;
+if ~isempty(boudat)
+    for k = 1: length(ibtype)
+        sm = sm + sum(~(boudat.ibtype - ibtype(k))) ;
+    end
 end
 if ( sm > 0 ) 
     fprintf( fid, '%d  \t \t ! NFFR \n', f15dat.nffr ) ;