diff --git a/src/gui/mainwindow.cpp b/src/gui/mainwindow.cpp
index e3115d8..df18ae1 100644
--- a/src/gui/mainwindow.cpp
+++ b/src/gui/mainwindow.cpp
@@ -61,7 +61,7 @@ MainWindow::MainWindow()
         auto locations = QStandardPaths::standardLocations(QStandardPaths::DataLocation);
         for (auto location : locations) {
             if (QFile::exists(location + QString("/Benutzerhandbuch.pdf"))) {
-                QDesktopServices::openUrl(location + QString("/Benutzerhandbuch.pdf"));
+                QDesktopServices::openUrl(QUrl(QString("file:///") + location + QString("/Benutzerhandbuch.pdf"), QUrl::TolerantMode));
             }
         }
     });
@@ -391,4 +391,4 @@ void MainWindow::closeEvent(QCloseEvent* event)
 {
     writeGeometry();
     event->accept();
-}
\ No newline at end of file
+}