While working on the layout of a new custom menu, I discovered that the hook_menu process is not working on my D7.12 local site. As a test I enabled the Menu_example module and found that it will not generate menu items in the navigation menu, although it did a week or two ago. So far I have reinstalled all Drupal 7.12 files and confirmed that the module file hook_menus are being read (using dsm). I am at a loss as to what else can be preventing the menu links from being installed.

Does anyone have any similar experiences or suggestions on how to track this problem down to its source?