Hi Fern
People are reporting issues with NU16 and windows 8.1, I have Nu15 and on the user interface at the top right hand side there is smart updates I don’t know if this will help.
Norton launches the windows defragmentation tool so you may like to try using the windows defragmentation tool?
Or try this defragmentation tool it is recommended by regular users of the Norton forum.
https://www.piriform.com/defraggler
ATB
intesec