diff --git a/src/libstore/build/substitution-goal.cc b/src/libstore/build/substitution-goal.cc
index 7deeb4748..0152f1808 100644
--- a/src/libstore/build/substitution-goal.cc
+++ b/src/libstore/build/substitution-goal.cc
@@ -145,8 +145,10 @@ Goal::Co PathSubstitutionGoal::init()
     /* None left.  Terminate this goal and let someone else deal
        with it. */
 
-    worker.failedSubstitutions++;
-    worker.updateProgress();
+    if (substituterFailed) {
+        worker.failedSubstitutions++;
+        worker.updateProgress();
+    }
 
     /* Hack: don't indicate failure if there were no substituters.
        In that case the calling derivation should just do a
@@ -158,7 +160,7 @@ Goal::Co PathSubstitutionGoal::init()
 }
 
 
-Goal::Co PathSubstitutionGoal::tryToRun(StorePath subPath, nix::ref<Store> sub, std::shared_ptr<const ValidPathInfo> info, bool& substituterFailed)
+Goal::Co PathSubstitutionGoal::tryToRun(StorePath subPath, nix::ref<Store> sub, std::shared_ptr<const ValidPathInfo> info, bool & substituterFailed)
 {
     trace("all references realised");
 
diff --git a/src/libstore/build/substitution-goal.hh b/src/libstore/build/substitution-goal.hh
index c1de45379..f2cf797e5 100644
--- a/src/libstore/build/substitution-goal.hh
+++ b/src/libstore/build/substitution-goal.hh
@@ -66,7 +66,7 @@ public:
      */
     Co init() override;
     Co gotInfo();
-    Co tryToRun(StorePath subPath, nix::ref<Store> sub, std::shared_ptr<const ValidPathInfo> info, bool& substituterFailed);
+    Co tryToRun(StorePath subPath, nix::ref<Store> sub, std::shared_ptr<const ValidPathInfo> info, bool & substituterFailed);
     Co finished();
 
     /**