"Tools", "options", "remember passwords for sites" becomes unchecked. Why?
I check the box "remember passwords for sites". then later, after using Norton identity safe, the box becomes unchecked.
Wšě wotmołwy (4)
It's possible that your Norton add-on is disabling the built-in Firefox feature to prevent confusion, i.e., saving passwords in two different places.
Check it in safemode.
if you still have the problem
Create a new profile as a test to check if your current profile is causing the problems.
See "Basic Troubleshooting: Make a new profile":
It appears, per cor-el, that Norton is aware of this issue,( and has for some time) but has not yet come up with a fix. It would be nice if they provided a definitive fix for this problem.