I have deleted some old categories and updated the main menu navigation but the list is not updating on the website. Checked cache and cookies. When I initially select the new menu I can see it then when I hit save it reverts to the old menu.
When editing themes or working with previews use a browsers private|incognito mode to skip local browser cache annoyances.
Be sure you are working on the published theme and not an unpublished theme or viewing a preview.
Be sure the menus have different names or you are selecting the proper menu name if you are using a theme setting to assign a navigation menu to the theme.
Toggle it off and on again with saves: Try clearing the setting entirely then assigning a object