diff --git a/gui/mainwindow.cpp b/gui/mainwindow.cpp
index b7f04b269..b6282a69b 100644
--- a/gui/mainwindow.cpp
+++ b/gui/mainwindow.cpp
@@ -359,6 +359,22 @@ void MainWindow::UncheckAll()
     ToggleAllChecked(false);
 }
 
+void MainWindow::closeEvent(QCloseEvent *event)
+{
+    // Check that we aren't checking files
+    if (!mThread.IsChecking())
+        event->accept();
+    else
+    {
+        QString msg(tr("Cannot exit while checking.\n\n" \
+                       "Stop the checking before exiting."));
+        QMessageBox *box = new QMessageBox(QMessageBox::Warning,
+                                           tr("cppcheck"), msg);
+        box->show();
+        event->ignore();
+    }
+}
+
 void MainWindow::ToggleAllChecked(bool checked)
 {
     mActionShowAll.setChecked(checked);
diff --git a/gui/mainwindow.h b/gui/mainwindow.h
index 6c1b5572b..d79e66eb1 100644
--- a/gui/mainwindow.h
+++ b/gui/mainwindow.h
@@ -141,6 +141,11 @@ protected slots:
     void ResultsAdded();
 protected:
 
+    /**
+    * @brief Event coming when application is about to close.
+    */
+    virtual void closeEvent(QCloseEvent *event);
+
     /**
     * @brief Helper function to toggle all show error menu items
     * @param checked Should all errors be shown (true) or hidden (false)
diff --git a/gui/threadhandler.cpp b/gui/threadhandler.cpp
index c7a5a271c..37df356b0 100644
--- a/gui/threadhandler.cpp
+++ b/gui/threadhandler.cpp
@@ -71,6 +71,11 @@ void ThreadHandler::Check(Settings settings, bool recheck)
     }
 }
 
+bool ThreadHandler::IsChecking() const
+{
+    return mRunningThreadCount > 0;
+}
+
 void ThreadHandler::SetThreadCount(const int count)
 {
     if (mRunningThreadCount > 0 ||
diff --git a/gui/threadhandler.h b/gui/threadhandler.h
index 21bb8d93b..25de349aa 100644
--- a/gui/threadhandler.h
+++ b/gui/threadhandler.h
@@ -85,6 +85,12 @@ public:
     */
     void Check(Settings settings, bool recheck);
 
+    /**
+    * @brief Is checking running?
+    *
+    * @return true if check is running, false otherwise.
+    */
+    bool IsChecking() const;
 
 signals:
     /**