diff --git a/src/plugins/coreplugin/coreimpl.cpp b/src/plugins/coreplugin/coreimpl.cpp
index c6da6362d44e25685f6ab00ef70fada45530f034..d072e8df091840d722b3f010bcd6f486248b3248 100644
--- a/src/plugins/coreplugin/coreimpl.cpp
+++ b/src/plugins/coreplugin/coreimpl.cpp
@@ -61,6 +61,11 @@ CoreImpl::CoreImpl(MainWindow *mainwindow)
     m_mainwindow = mainwindow;
 }
 
+CoreImpl::~CoreImpl()
+{
+    m_instance = 0;
+}
+
 QStringList CoreImpl::showNewItemDialog(const QString &title,
                                         const QList<IWizard *> &wizards,
                                         const QString &defaultLocation)
diff --git a/src/plugins/coreplugin/coreimpl.h b/src/plugins/coreplugin/coreimpl.h
index d04defd31814283e0c7476dab3ff47d02b30f58a..50a8a673fbd101768c84fa20aa25832d2d1e1250 100644
--- a/src/plugins/coreplugin/coreimpl.h
+++ b/src/plugins/coreplugin/coreimpl.h
@@ -42,7 +42,7 @@ class CoreImpl : public ICore
 
 public:
     CoreImpl(MainWindow *mainwindow);
-    ~CoreImpl() {}
+    ~CoreImpl();
 
     QStringList showNewItemDialog(const QString &title,
                                   const QList<IWizard *> &wizards,
diff --git a/src/plugins/projectexplorer/debugginghelper.cpp b/src/plugins/projectexplorer/debugginghelper.cpp
index 495996e4506c8353df7805e6fbc557659b9f0fc8..9c091557c0193581028a5d516f179ed3a07af06d 100644
--- a/src/plugins/projectexplorer/debugginghelper.cpp
+++ b/src/plugins/projectexplorer/debugginghelper.cpp
@@ -113,6 +113,8 @@ QStringList DebuggingHelperLibrary::debuggingHelperLibraryLocationsByInstallData
 
 QString DebuggingHelperLibrary::debuggingHelperLibraryByInstallData(const QString &qtInstallData)
 {
+    if (!Core::ICore::instance())
+        return QString();
     const QString dumperSourcePath = Core::ICore::instance()->resourcePath() + QLatin1String("/gdbmacros/");
     QDateTime lastModified = QFileInfo(dumperSourcePath + "gdbmacros.cpp").lastModified();
     // We pretend that the lastmodified of gdbmacros.cpp is 5 minutes before what the file system says