Ran Norton for a really long time, but believe me, there are free programs on the internet that work much better than Norton. They also use less resources than the Symantec products. That's not to say Norton is a bad product, just that it's a resource hog (sucks the RAM up and doesn't release it). Also, the statement that it "runs unobtrusively in the background" is a complete lie. When it's doing its thing, you experience slowdown, and if you don't have a lot of RAM, can come to a complete slowdown or freeze up.
Since I remove Norton from my computer, I've been running AVAST Anti Virus and Comodo firewall. If you just purchased Norton, you're stuck with it until your subscription runs out unless you decide to uninstall it and take the loss.
You might try to go to the Symantec site and find out if there is a fix for the problem.