WordPress 3.5 Categories, Menu missing

Hi all

I have an issue with WP 3.5

When installing new WP after adding category for posts and then saving it, it disappear. To the extend that even uncategorised is gone.

Same situation with menus. When I create a menu, add some pages, then save as my main menu it is saving but as soon as I will navigate back to menus it is gone.

Both issues looks the same, both inputing data to database.

Looks like backend / dashboard of WP is not pulling information from DB.

Anyone with the same problem? and hopefully solution?

Thanks
Kris