So as many others, I was forced to upgrade my Firefox and consecutively, my Norton product too, which disabled the Norton vault functionality. I spent hours reading various forums and sites trying to get it back. Haven't succeeded yet. I also tried the chat support two times and also czech hotline, but they still repeat the same - it is not supported, use Chrome... 
I tried to downgrade Firefox to version 44, later to 42, 40, 39 and even 38 (all what they call clean install). And I also fully removed the newest Norton version and installed v 21.7.0.11 with all the possible updates (updates, fixes, restarts, updates, fixes, restarts, updates, shutdown, cold start...). I thought this all could do the trick.
So now, I have Norton Internet Security v 21.7.0.11 and Forefox v 39.0.3 which should be compatible. I have the Norton toolbar plugin installed and allowed in the browser ( v 2014.7.12.35) but it doesn't show up. Norton says it is installed for Firefox, but disabled.
I have already spent days and nights trying to fix this issue. In the end, the czech hotline (the woman there honestly had no clue about what is possible and what not - talking about firefox upgrading itself anyway if I downgrade...) suggested doing system restore (few days back when it still worked) - but I know it is not suggested in general...
First of all, I would like to ask, is it even possible get the working combination of FF and Norton back (any versions)? I might be doing something wrong... 
Second, if everything failed, should I still try the system restore (anyone who has tried it and it work for them?)
Thank you for the help in advance and sorry for my bad English.
Oh, by the way, the working FF version was 34 and sadly don't remember the version of NIS (but for sure older than the v 21.7.0.11) - the only thing that kept me from upgrading both products was Norton toolbar functionality - need it for my work and daily routines.