Problem

The 'Administration' menu is not showing. Instead, only a 'Hide All' link is visible.

Cause

The 'Admin Menu Section' plugin was disabled. At this time Atlassian is unsure of a root cause. We have seen this occur infrequently after upgrades or LDAP configuration changes.

Workaround

The plugin can be re-enabled by visiting it's URL directly:

http://<baseurl>/secure/admin/jira/ViewPlugins.jspa?mode=enable&pluginKey=jira.webfragments.admin

Or 

http://<base_url>/jira/secure/admin/ViewApplicationProperties.jspa 

This should re-enable the plugin and display the 'Admin Menu Section'.

Resolution

The ability to disable this plugin has been removed. The workaround can correct any lingering invalid state.