diff --git a/src/plugins/projectexplorer/userfileaccessor.cpp b/src/plugins/projectexplorer/userfileaccessor.cpp
index 8ab124ef963111a56d6a462d5a51c957c688daab..083866b1f65c2e7a5a14fe1f8e171bbef68c5f91 100644
--- a/src/plugins/projectexplorer/userfileaccessor.cpp
+++ b/src/plugins/projectexplorer/userfileaccessor.cpp
@@ -1250,7 +1250,7 @@ QVariantMap Version6Handler::update(Project *, const QVariantMap &map)
 
             QVariantMap buildSteps;
             QVariantMap cleanSteps;
-            QVariantMap &originalBc = targetIt.value().toMap();
+            const QVariantMap &originalBc = targetIt.value().toMap();
             QVariantMap newBc;
 
             QMapIterator<QString, QVariant> bcIt(originalBc);