diff -U 3 -dHrN -- b/gnuhealth_camera/__init__.py a/gnuhealth_camera/__init__.py
--- b/gnuhealth_camera/__init__.py	2018-11-27 00:07:32.000000000 +0100
+++ a/gnuhealth_camera/__init__.py	2019-11-11 19:46:58.148898162 +0100
@@ -166,7 +166,12 @@
             set_attachment(data, frame)
             break            
 
-        if keypressed == ord('q'):
+        # Cleanup / Destroy window when q key is pressed or when closing
+        # the window via alt+f4
+        if (keypressed == ord('q')):
+            break
+
+        if (cv2.getWindowProperty('== GNU Health Camera ==', cv2.WND_PROP_VISIBLE) < 1):            
             break
 
         if  keypressed == ord('h'):