Admin menu sometimes doesn't show up I'm having some strange issues with the Drupal admin menu system. I can't reproduce it reliably, but these are the steps that usually cause the problem:


Go to /user and log in. This works as expected and redirects me to the user page, where I see the admin menu.
Navigate to the front page, either by clicking a link on the page or by manually entering the / address.
Observe that there is no admin menu.
Refresh the home page (possibly a couple of times), and the admin menu may eventually appear.


I've tried both Firefox and Chrome in private browsing sessions, as well as clearing the Drupal admin menu cache. I'm completely thrown by this, as checking in Firebug/Chrome developer tools reveals the SESSxxxx cookie properly set and not changing between when the menu is shown and when it isn't.

Related questions refer to CSS/JS aggregation issues as well as permissions errors. It seems unlikely that at least the latter problem would be so unreliable.

I have Drupal 7 running on PHP 5.4.39/Apache 2.2.22 under Debian wheezy.
The few times i have had a similar issue i have resolved it by turning off 'Cache menu in client-side browser' on this page admin/config/administration/admin_menu