Update-manager keeps popping up repeatedly :

Keeping system up-to-date is always a good thing but sometimes you don’t have time to install the updates. In that case the user must be given choice if he wants to enable or disable the update check. Sadly somehow Ubuntu developers forgot this while packaging Update-manager which is responsible for installing updates to system. After the clean install, it kept nagging several times in a hour and this was the worst annoyance for me. Going into settings and disabling the “Check automatic updates” didn’t work out so well.

In previous releases “update-manager” would check for updates periodically and if there were any updates available it would show a bubble tooltip to indicate that new updates are available. To restore this behavior and to fix the nagging window of “update-manager”, type in terminal

gconftool -s –type bool /apps/update-notifier/auto_launch false

All gnome applications settings are saved in a repository manged by GConfig daemon and gconftool is a command line tool to manipulate these preferences. Above command changes setting of “update-notifier” so it will not launch automatically.