In a site which has been running for some time, and, to my knowledge, has not had any updates or modifications other than content in the last week, The categories for all post types have dissapeared and if I go to the menus page in admin, there are no menus, although the site is displaying at least 2 different menus.
I have checked the database and the table with the categories in it is still there and all categories are still there.
I tried adding a new category and it shows in the list after adding, but if I navigate away from the categories page in adin and then back again, the new category no longer shows.
The catgories page also shows the count of items in the page correctly and increases the count for eact additional category added.
I can also doa search and it returns a reduced count but nothing in the list.
To my knowledge, nothing has been done to this site at all in the last 7 days but overnight, this has happened.
any ideas would be greatly appreciated.
I have only found one other post which details my problem exactly, but no solution is documented there and the post is closed.