This is not a new problem, but I have been continually puzzled by the failure of LiveUpdate to do its job completely. I've experience this with Norton Internet Security at least for the past several years. I'm currently running NIS 2011.
Under Computer Protection on the NIS main screen, there is always a green font message about how many hours, minutes or seconds ago LiveUpdate was automatically run. If I click on Run LiveUpdate to the left of that green font message, a new window opens showing the manually-started Norton LiveUpdate sequence.
That manual process almost invariably checks, downloads, processes and installs between one and six new updates.
Why weren't those identical updates done automatically several hours, minutes or seconds ago as was indicated by NIS? Why should it be necessary to overrride the automatic feature by manually clicking on Run LiveUpdate and downloading and installing updates that weren't done properly?
There are different schedules for different types of content and updates.
The product frequently, 5 to 15 minutes, checks for pulse updates, this is a process that requires very little bandwidth and little CPU and IO resources.
Other content is checked less frequently, 4 to 24 hours, and updating this type of content requires more processing power and more bandwidth.
Update checks are further suppressed while you are actively using the computer, this is done to prevent the above mentioned resource impact interfering with your work or games.
When silent or quiet mode is engaged, update checks, including pulse updates, are suppressed.
When the system goes idle, all update checks that are overdue and have been suppressed will be downloaded.
When you manually run LU, all content is checked, regardless of schedule, and regardless of impact on performance.
As such you may see updates in the UI that have either been suppressed, or that has yet to be scheduled.
The main UI shows your protection content status that is based on pulse updates, and pulse updates are downloaded frequently even when not idle.
I always understood that Pulse updates were expected to be light on resources and that regular updates would require additional bandwidth. I've alway kept Silent Mode off/disabled.
If I understand you correctly, if I leave my computer idle (overnight for example) it is expected that most non-Pulse updates will probably be automatically installed without my manual input. Is that correct?
It also depends on the time since it last ran. So as not to overload or crowded the OS, Norton does not run the task every few minutes. I'm assuming there is a time interval between runs. The best way to be fully protected is to manually run liveupdate. I always run liveupdate the first thing I do in the morning (when I switch on the computer) and when I switch off the computer for the night. Also every few hours I manually run LiveUpdate just in case.
Live Update will run typically between 2-3 times per day and once 1-2 times per day on the weekend. Depending on when it last ran there is a good chance that while you are sleeping it would probably run if it had not already had a chance to run before that.
However as others have said, running it manually first thing in the morning is not a bad habit to get into. The most critical updates however are the pulse updates which run approximately every 10 minutes.