hi, this is a scam tactic that is trying to trick you into installing malware, so don't download or execute this kind of stuff just because of a popup or redirect on a website! updates are handled automatically by firefox so you don't have to download anything for that (and you can always initiate a manual check for updates in the firefox menu ≡ > help ? > about firefox).

we suspect this is coming form "malvertising" (=ads placed on legitimate websites that redirect you to this fraudulent message), so using an adblocking addon like https://addons.mozilla.org/firefox/addon/ublock-origin/ would also help with that.

I found a fake Firefox update

Thank you for the amazingly quick response! I still have to ask how is it possible for anyone to make Firefox go to this erroneous address upon startup without altering my startup page (which has not been changed)? I have a BSCS degree and I still can't imagine how this is possible. Is there any way to block this type of attack to your knowledge? Thanks for any info you can offer, Scott

what is your startpage? if it has ads embedded that's probably the source of the error. those malicious ads use javascript to redirect you away from the page you are currently visiting to this scam. as long as those advertising networks are totally out of control, i'd recommend installing an adblocking extension to protect yourself!

I did indeed install the ad blocker recommended in your initial response. My start page is www.google.com, which normally doesn't display any advertising... Perhaps I'd better let Google know about this as well...

Again, thanks for your excellent response time and very competent advice, Scott