diff --git a/dune/tectonic/myblockproblem.hh b/dune/tectonic/myblockproblem.hh
index 1cf7ede03ff2480e41d259a047a374bfe5da9cc8..9a34464617d3b716373af6367bb75d4eae69cbc5 100644
--- a/dune/tectonic/myblockproblem.hh
+++ b/dune/tectonic/myblockproblem.hh
@@ -77,6 +77,8 @@ template <class MyConvexProblemTypeTEMPLATE> class MyBlockProblem {
     VectorType v = projected_v;
 
     double const vnorm = v.two_norm();
+    if (vnorm == 0) // This can (and needs to be able to) be very small
+      return 0.0;
 
     v /= vnorm; // Rescale for numerical stability