Do some more checks, maybe one of them is the reason for a crash.

src/plugins/qt4projectmanager/profilereader.cpp

@@ -46,7 +46,10 @@ ProFileReader::~ProFileReader()
 }
 
 void ProFileReader::setQtVersion(QtVersion *qtVersion) {
+    if (qtVersion)
         m_option.properties = qtVersion->versionInfo();
+    else
+        m_option.properties.clear();
 }
 
 bool ProFileReader::readProFile(const QString &fileName)

src/plugins/qt4projectmanager/qt4projectconfigwidget.cpp

@@ -146,8 +146,10 @@ void Qt4ProjectConfigWidget::updateDetails()
     QString versionString;
     if (m_pro->qtVersionId(m_buildConfiguration) == 0) {
         versionString = tr("Default Qt Version (%1)").arg(version->name());
-    } else {
+    } else if(version){
         versionString = version->name();
+    } else {
+        versionString = tr("No Qt Version set");
     }
     // Qt Version, Build Directory and Toolchain
     m_ui->titleLabel->setText(tr("using Qt version: <b>%1</b><br>"

src/plugins/qt4projectmanager/qt4runconfiguration.cpp

@@ -629,14 +629,20 @@ QString Qt4RunConfiguration::dumperLibrary() const
 {
     Qt4Project *pro = qobject_cast<Qt4Project *>(project());
     QtVersion *version = pro->qtVersion(pro->activeBuildConfiguration());
+    if (version)
         return version->debuggingHelperLibrary();
+    else
+        return QString::null;
 }
 
 QStringList Qt4RunConfiguration::dumperLibraryLocations() const
 {
     Qt4Project *pro = qobject_cast<Qt4Project *>(project());
     QtVersion *version = pro->qtVersion(pro->activeBuildConfiguration());
-    return version->debuggingHelperLibraryLocations();;
+    if (version)
+        return version->debuggingHelperLibraryLocations();
+    else
+        return QStringList();
 }
 
 void Qt4RunConfiguration::setBaseEnvironmentBase(BaseEnvironmentBase env)