diff --git a/AMDiS/src/DOFMatrix.cc b/AMDiS/src/DOFMatrix.cc
index 774aad5f0e6e5d75325f13e54edc98c281c9c70f..7d4a579cd617fc45cf23a55a40082f0800e49093 100644
--- a/AMDiS/src/DOFMatrix.cc
+++ b/AMDiS/src/DOFMatrix.cc
@@ -218,6 +218,8 @@ namespace AMDiS {
 
   void DOFMatrix::freeDOFContent(int index)
   {
+      if (matrix.nnz() == 0) return;
+
     using mtl::tag::major; using mtl::tag::nz; using mtl::begin; using mtl::end;
     namespace traits= mtl::traits;
     typedef base_matrix_type Matrix;