Something is trying to trick Firefox into accepting an insecure update

Martin Brinkmann
Oct 19, 2011
Updated • Mar 9, 2015

For the last two days I have received popup messages when running Firefox. They stated "Update Failed. Something is trying to trick Firefox into accepting an insecure update. Please contact your network provider and seek help".

Since I have not changed a thing in that time that would affect Firefox's update mechanism I first thought that it was a issue with the Firefox updating process itself.

Still, I decided to do some research and found out that I'm not the only user affected by the Update Failed message.

I received the error message running Firefox Aurora, others running the latest stable version of the browser.

First thing I noticed was that the Firefox Aurora version that I was running was not automatically updated anymore. The version was a few days old and checking manually for updates returned the message that the browser was up to date (turned out later it was not).

When you look at the Firefox Help forum you get a lot of recommendations. This ranges from malware to plugins or extensions that affect the updating mechanism to files that previous updates left behind in the Firefox installation folder.


If you have files in the defaults\pref folder in the Firefox installation folder (C:\Program Files\Mozilla Firefox\defaults\pref) folder other than the file channel-prefs.js then the updater didn't remove those files or wasn't able to do that because other software (possibly visualization software) had prevented that. That causes Firefox to override correct prefs with older prefs from firefox.all.

Enter about:config in the Firefox address bar and filter for the term app.update.url there. Make sure the url begins with

Another possible cause that was mentioned quite often were third party extensions and plugins.

Google Update was mentioned for instance several times in various Mozilla forum threads. I'm personally not really sure why the plugin gets installed into Firefox in the first place. I did notice that a Pando Media Booster plugin was installed on my system which I have not heard about before. I suspect that it was installed with the Might and Magic: Heroes VI game that I installed recently as it is commonly installed with games, especially MMOs.

Uninstalling the software from my system did not resolve the updating issue. It is not conclusive if the plugin had something to do with it though.

My solution was the following: I went to the Mozilla Firefox download page and re-downloaded the latest version of the web browser from there. I then installed it which did update my version of the browser to the latest version. It is too early to say if it fixed the issue completely, but I have not received the message ever since.

Something is trying to trick Firefox into accepting an insecure update
Article Name
Something is trying to trick Firefox into accepting an insecure update
A fix for the Firefox update error about an insecure update that you may get when the browser tries to download and install an update.

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  1. Joe said on September 1, 2017 at 5:15 am

    Maybe you should take the error at face value.

  2. Equorial said on March 14, 2013 at 6:20 am

    I’ve had the same ‘warning’ twice now, using Firefox 19 and no notable changes or updates to what I’ve been using for years upon years …so it must be associated with certain websites (not necessarily malicious ones, as it just happened while visiting a Debian “how to install” site that is Debian’s #1 site). I’m anonymized though, and perhaps that has something to do with it, yet I also doubt that is the culprit ….but possibly the government has something to do with it. They mess with everything it seems. Cheers!

  3. Elaine said on February 29, 2012 at 12:13 am

    I have the problem with Firefox 10.0.1. I will try your fixes. Thanks for doing the research for the rest of us.

  4. Paul(us) said on October 19, 2011 at 12:41 pm

    I do not have the problem with main Mozilla Firefox 7.01. Mayday this is because i have not installed the Google update add-on’s and Pando Media Booster plugin?

    1. Martin Brinkmann said on October 19, 2011 at 1:13 pm

      Only a minority of users will experience the issue, so no need to worry.

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