NAV Removes Remembered UserNames?

I am running the current version of Norton Antivirus with automatic updates and renewal.  One problem, when NAV runs a full scan, it removes all the remembered usernames I have set for certain websites.  What do I have to do to get it to stop removing my Remembered usernames on my computer when it runs the full scan?  It never warns of any issues with them, just removes  them.  The full scan does not run on a daily basis, just every now and then.  So, what do I have to do (I want to retain my remembered usernames)?

Thanks

gumboman