Latest 6.7.1.6 is broken but previous version 6.6.3.5 still works under Win 10. Latest version first asks to login to Norton account then unable to login to Password Manager and generates error that says "something went wrong". Removed 6.7.1.6, reinstalled 6.6.3.5 and everything works again.

EDIT: changed star rating from 1 star to 4 stars since previous version 6.6.3.5 works great before updating to 6.7.1.6. shortly after uploaded to Mozilla.