diff --git a/spot/twaalgos/isdet.cc b/spot/twaalgos/isdet.cc
index a63892058..5885351ed 100644
--- a/spot/twaalgos/isdet.cc
+++ b/spot/twaalgos/isdet.cc
@@ -174,7 +174,6 @@ namespace spot
                   if (!bdd_implies(t.cond, available))
                     {
                       semi_det = false;
-                      std::cerr << "Failed on state " << src << '\n';
                       goto done;
                     }
                   else