Norton 2008 also have the option to run a Quickscan each time new definitions has been received.
The alert that you are seeing is maybe referring to the Quickscan which is known to check every 5 days, if the task has been run or not.
To determine if this is happening to your system, note the "Last run" date for Quickscan.
When the warning the Virus and Spyware scan has not completed occurs... allow it to run the said scan. Review the "Last run" date for Quickscan for changes. If the date changed after the scan or while the scan is running... it means the above Quickscan task triggers the 'warning' and not the Full System scan.
To hopefully fix the issue, you might want to do the following:
1. Run LiveUpdate manually to get updates
2. Do a trial & error fix: Uncheck the option to run quickscan. Click OK to apply. Re-check the said option. Click OK to apply.
If it's not the quickscan or if the problem is not solved... please tell us what version of NIS 2008 is installed? Open NIS>Help & Support>About
The new version is Norton Internet Security 2008 v220.127.116.11 (it has bug fixes)
If you have earlier version, you might want to download the new version from their website
You can install on top of existing version but it is recommended to remove old version. Use Norton Removal Tool to remove the old version.
Next, check the version of LiveUpdate. The new version is v18.104.22.168. You can download the new LiveUpdate here.
I use NIS 2008 and have a full system scan scheduled for every Friday evening and this is carried out without any problems. So why is it that every Thursday when I turn on my computer there is a warning that a Virus and Spyware scan has not been completed? The scan schedule allows for weekly scans so why do I get a warning after 6 days? Any suggestions please.