diff --git a/app/ui/main_window.py b/app/ui/main_window.py
index f071f47..ef899ab 100644
--- a/app/ui/main_window.py
+++ b/app/ui/main_window.py
@@ -1,6 +1,6 @@
 ''' app/ui/main_window.py '''
 from PyQt6.QtCore import Qt, QTimer
-from PyQt6.QtWidgets import QMainWindow, QWidget, QHBoxLayout, QTextEdit, QLabel, QDialog, QToolButton, QStatusBar
+from PyQt6.QtWidgets import QMainWindow, QWidget, QHBoxLayout, QTextEdit, QLabel, QDialog, QToolButton, QStatusBar, QFileDialog
 from PyQt6.QtWidgets import QToolBox
 from PyQt6.QtGui import QIcon
 from .widgets.menubar import MenuBar
@@ -98,9 +98,9 @@ class MainWindow(QMainWindow):
         self.topbar.add_button("meas_devices", "Devices", QIcon.fromTheme(QIcon.ThemeIcon.Printer), self.vmdev_connect_from_dialog)
         self.topbar.add_button("meas_start", "Start", QIcon.fromTheme(QIcon.ThemeIcon.MediaPlaybackStart), self.measure_start)
         self.topbar.add_button("meas_stop", "Stop", QIcon.fromTheme(QIcon.ThemeIcon.MediaPlaybackStop), self.measure_stop)
-        self.topbar.add_button("meas_save", "Save", QIcon.fromTheme(QIcon.ThemeIcon.DocumentSaveAs), self.save_file)
+        self.topbar.add_button("meas_save", "Save", QIcon.fromTheme(QIcon.ThemeIcon.DocumentSaveAs), self.measurement_save)
         self.topbar.add_separator()
-        self.topbar.add_button("app_exit", "Exit", QIcon.fromTheme(QIcon.ThemeIcon.ApplicationExit), self.exit_app)
+        self.topbar.add_button("app_exit", "Exit", QIcon.fromTheme(QIcon.ThemeIcon.ApplicationExit), self.app_exit)
         self.addToolBar(Qt.ToolBarArea.TopToolBarArea, self.topbar)
 
         # disable the Stop and Save buttons
@@ -183,7 +183,10 @@ class MainWindow(QMainWindow):
 
         self.topbar.disable_button("meas_start")
         self.topbar.disable_button("meas_devices")
+        self.topbar.disable_button("meas_save")
         self.topbar.enable_button("meas_stop")
+        self.w_plot.clear_data()
+
         script = 100
         measurement_name = "guitest"
         led_script = LedScript(script=script)
@@ -262,21 +265,26 @@ class MainWindow(QMainWindow):
     def measurement_is_running(self):
         return self.proc_measure is not None
 
-    def open_file(self) -> None:
+    def measurement_save(self) -> None:
         """
-        Event handler for the "Open" button. Displays the "Open File" dialog.
+        Save the last measurement data to a file.
         """
-        print("Open")
+        if self.data_collector is None:
+            raise RuntimeError("Can not save, not data collector initialized")
+        csv = self.data_collector.to_csv()
+        # open file dialog
+        filename = self.data_collector.dirname + ".csv"
+        file_name, _ = QFileDialog.getSaveFileName(self, "Save File", filename, "CSV Files (*.csv)")
+        if file_name:
+            with open(file_name, "w") as f:
+                f.write(csv)
+            self.set_status(f"Saved data to {file_name}")
+        else:
+            self.set_status(f"Aborted saving data, no file selected")
 
-    def save_file(self) -> None:
+    def app_exit(self) -> None:
         """
-        Event handler for the "Save" button. Displays the "Save File" dialog.
-        """
-        print("Save")
-
-    def exit_app(self) -> None:
-        """
-        Event handler for the "Exit" button. Closes the application.
+        Closes the application.
         """
         self.close()