The save function does not work properly. This has happened twice and is very painful. Whether you click the save icon or go through the File menu or via the shortcut keys, it doesn't work. It work...
I see release 5.0 out for a while. But no such report. From your post it looks intermittent problem. Do you face when saving a project or script or something else? What happens when you right click on the project and remove, does it prompt for save changes and it does after confirmation?