Mozilla released Firefox12 and this time it was with one less prompt. There was no UAC prompt today when my Firefox automatically got updated to version 12. Though not totally invisible the update didn't require any human interaction. A completely silent updater will be the feature of Firefox 13. The reason why user will not see the UAC prompt during update to Firefox 12 is that Firefox uses a service to install itself. The service called 'MozillaMaintenance' has privileges to change system files and thus doesn't ask the user for permission.
