The problem with Norton has been fixed. I tracked the bandwidth down to our main update server downloading antivirus updates every 10 minutes – the same updates every 10 minutes. Once I disabled “continuous live updates” which should only attempt to get live updates if the definitions are more than 10 days old (they were uptodate) , I found it was *still* trying to download the updates. A long call to Symantec helpline and he asked me to check everything that I had already done, which was comforting to know that I was on the right track. We re-enabled continuous updates,clicked apply and then disabled it again….and the updates still kept being downloaded every 10 minutes. It was decided that maybe a reboot would force the system to reread the configuration and start downloading once a day (although I had already done one reboot). I scheduled a reboot for 10pm and went home – At 7pm the updates stopped.Reboot at 10pm and a scheduled download at 4am – as per configuration. Very strange.