Hi, Mozilla Firefox does not ask for a password to update.

It is likely to be a fake update designed to infect you with malware which we have seen a lot of recently, although it is unusual for Linux.

If you are in any doubt about the authenticity of update pop-ups etc., it's always best to ignore them and check for genuine updates yourself, by opening the 3-bar menu > Help (question mark at bottom right) > About Firefox. More - Update Firefox to the latest release.

If your question is resolved by this or another answer, please take a minute to let us know. Thank you.

I followed the procedure there but I only get a small window that tells me I am at version 41.0 but does not go to or even give the option of updating, so "The About Firefox window will open and Firefox will begin checking for updates and downloading them automatically. " is wrong. Because of Mint? I don't know.

I haven't used Mint since 2006 or 2007, so I can't advise to you exactly how to proceed.

You posted here with: User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:41.0) Gecko/20100101 Firefox/41.0

That looks like a non-Mozilla build of Firefox, which would get updated from the Mint or Ubuntu repository, not from Mozilla using the Help > About Firefox button.

Which version of Mint do you have? It may be too old to update from the program repository; you may need to update Mint to get later versions of Firefox.

As far as updating Firefox overall on Linux platforms, Firefox 46.0 received a change that will affect older Linus operating system. https://www.mozilla.org/en-US/firefox/46.0/releasenotes/ GTK3 integration (GNU/Linux only) Not sure is that holds true for Ubuntu / Mint or not, but we have seen a number of postings about problems with GTK2 in Firefox 46 and later versions

Looks like a duplicate here - https://support.mozilla.org/en-US/questions/1143106