Firefox 43 Automatically Disables Unsigned Add-ons

Firefox-logo-smStarting with the recent release of version 43, Mozilla is no longer allowing “unsigned” add-ons to run in Firefox and is automatically disabling any such add-ons during the update process. Unsigned add-ons are all browser extensions that have not been submitted to Mozilla for signing, including add-ons integrated into 3rd party software and extensions that have been published only on third-party websites.

The principle behind Mozilla’s move may be well intentioned – add-ons submitted to Mozilla for signing are checked for malware, compatibility and overall safety – however, the system is flawed in that it precludes a huge number of proven safe and reputable add-ons. A typical example is browser extensions which are integrated into popular software, such as web monitoring features included with antivirus products.

I’ve been using the free and trusted WordWeb software for years. WordWeb is a locally installed dictionary/thesaurus which allows users to highlight a word or phrase in any document and then, with a single click on WordWeb’s system tray icon, receive an instant definition including a list of synonyms – very handy for anyone who is a writer. Integrated into WordWeb is a browser extension called “one-click lookup” which provides the same functionality for web content.

So, my Firefox updates to version 43 recently and, to my dismay, ‘WordWeb one-click lookup’ is disabled with no option to enable it again.

wordweb disabled

(By the way: if you want to check your add-on status in Firefox, just click Tools in the main menu across the top of the browser and select Add-ons)

Now, I know for a fact that WordWeb is an established and popular software emanating from a reputable developer, I have no doubt that it is 100% safe. However, apparently, I am no longer allowed to make that decision.

Re-enabling Disabled Add-ons

add-ons for firefox2

As of Firefox version 43, any unsigned add-ons which have been disabled can be re-enabled again via the about:config settings:

  • Type about:config into Firefox’s address bar and hit Enter.
  • Click the I’ll be careful, I promise button
  • Search for xpinstall.signatures.required
  • Double click the entry to change the value to “false”

However, this is only a temporary solution, Mozilla is planning on removing this setting altogether in Firefox 44.

It should be noted that some extensions installed through third party sources may also be available on Mozilla’s official AMO website which only includes signed add-ons. You could also search there for possible (similar) alternatives to any unsigned add-ons you have installed.

I’m pretty sure that, eventually, most software developers and vendors will submit their browser extensions to Mozilla for signing. However, I doubt they’ll be in any hurry to do so and in the meantime many Firefox users will be deprived of some of their favorite extensions.

Firefox WebExtensions Coming


DCT reported on the eventual introduction of Mozilla’s new add-on platform, known as WebExtensions, back in August this year: Firefox Add-ons, Major Compatibility Changes Coming. Latest official Mozilla announcements are now suggesting that this new model will be fully implemented in Firefox 48, mooted for release in July, 2016: Mozilla’s official blog annoucment

The original announcement created a storm of protest among the Firefox community, with some developers vowing they would stop developing their add-ons for the browser. Many Firefox users also vowed to move to an alternative browser if Mozilla went ahead with the WebExtensions implementation.

One of the main reasons behind the negative reaction is Mozilla’s intention to deprecate Firefox’s permissive add-on model which currently allows for the creation of more powerful add-ons with deeper integration which are not possible in other browsers – and will no longer be possible in Firefox either under the new system.

So, it would appear that Mozilla is intent on moving Firefox away from the unique and versatile browser it once was and just adopting a sheep mentality.


18 thoughts on “Firefox 43 Automatically Disables Unsigned Add-ons”

  1. Jim, great article. Your last paragraph says it all. This is indeed too bad, and it will force me to another browser. I just don’t know of one that will work like FF used to. Not a Chrome fan, and definitely not a MS browser fan either. What are we going to do? So sad <:(

  2. Totally agree Jim. So sad that were have to be treated like little children who are unable to make decisions on our own. Bad on you Firefox, Mindblower!

    BTW. Merry Christmas; ho,ho,ho!!!

  3. Yes i had one, it disabled an extension ( it had been unsigned for about 2 updates ). .rather awkward, called Samfind bookmark toolbar so i had nothing there… did the about config, manually loaded the same bookmarks and just use the normal firefox bookmarks now – that was an hour or so totally wasted doing that.. They better not mess with the other one “classic theme restorer ” or it’s goodbye and off to another browser – shame if that happens – Kevin.

  4. Last I heard is that the pref switch removal won’t happen until v45, when Mozilla’s solution to the ‘problem’ will be ‘temporary’ add-on loading – non-signed add-ons can be installed for one browser session.
    If not, there’s always the ESR version for in the meantime (currently v38).

    1. Your are correct. The situation has been fairly fluid but I see the latest information emanating from Mozilla suggests that the preference switch will be removed as of v45.

      As for the “temporary” add-on loading option, well that’s primarily to allow developers to test their add-ons. I can’t see too may users having the patience to be constantly re-enabling unsigned add-ons for each and every session – what a pain in the you know what.

      And, of course, the ESR version will eventually catch up. According to the current Mozilla chart, ESR will be at v45 around April next year, at which time users will then be in exactly the same boat.

      I realize that you understand these are temporary solutions only SirPaul, I’m merely clarifying the situation for others. 🙂

      1. Great post Jim, I had the same problem with WordWeb one-click lookup. These
        new measures reduce the desirability of Firefox and one might just as well
        go back to Internet Explorer. Remember Murphy’s Law; “If it aint broke don’t
        fix it.”

  5. I like it when even Google Chrome says that an extension has taken over the home page settings, but still gives you the “option”, LOL, of disabling it, in settings. Takes the burden of disabling Browser Hijackers off the Malware and anti-virus scanners. A good browser, like a good anti-virus scanner, should be able to protect itself.

  6. The worldwide cancer of overregulation strikes again. If Mozilla were really concerned about user safety they would simply automatically test every add on in their catalogue. What’s the betting that Mozilla charge in some way for certifying add ons submitted to them to give them a sure fire revenue stream. The problem is that independent developers are the ones hit the most and they are the ones that produce the most innovative add ons. I checked mine and find that there are warnings on two of my regulalry used add ons including Sticky Password (my password manager. If that gets blocked then I shall move on from Firefox

  7. I’ve been using Firefox for years but have become increasingly unhappy with their ‘big brother’ attitude. Some of my favorite add-ons, including some of Mozilla’s, are unsigned (but completely safe) and are apparently going away. I tried 43.0.1 but when I saw that Favorites was ‘killed’ (blank) I reverted to 43.0 and plan on staying there, or earlier. My next step is another browser. Goodbye Firefox…

  8. Hi, I use “media hint” in order to view Netflix from USA and the Amazon/Prime movies on my computer here in Australia.
    Noticed in my Firefox Menu/Addons mananger that Media Hint had been disabled as it could not be verified.
    Strange thing is though, I can still access these sites and see the movies.
    I hadn’t known about the file being disabled until reading this article about Firefox.
    I’m wondering why there is such a notice when it is still working just fine?
    Both Mediahint and noscript have been disabled.
    Having not used “noscript” for some time and forgetting how to use it, I’m not bothered too much.
    But MediaHint is still going in Firefox no trouble.
    Any ideas on this? Seems weird to me.

  9. Gene De Lorenzo

    Out of curiosity, does anyone know if this action on Mozilla’s part will affect Pale Moon in any way? I understand that Pale Moon is somehow based on the same structure as Firefox, and although the browser is similar, it is different from the original. I have switched completely over to Pale Moon, and have no regrets, whatsoever. Pale Moon is what Firefox used to be before the infighting destroyed Mozilla. I was very pleasantly surprised to see just how easy it was to adopt to Pale Moon once it was installed. Virtually, all my extensions I had installed in Firefox worked fine in Pale Moon. I really hope that whatever Mozilla has planned for Firefox doesn’t ooze over to affect Pale Moon. One really needs to be a strong masochist to stick with Mozilla.

  10. I looked at Pale Moon after reading about how Firefox was going to change how addons would be implemented . I chatted on an official Pale Moon forum where I was told that Pale Moon will not ever be doing what Firefox is about to. Although there are some (many?) addons that are not compatible with both Firefox and Pale Moon, I have been happy with what does work with Pale Moon.

    The one area I had some trouble with Pale Moon is that some websites would not initially work with it, stating something like “you are using an old versions of Firefox”. Thankfully, there is a workaround for it, but it did take a little research to resolve conflicts. The one that would have made me stay with Firefox for now was my online banking site, I could log into it, but I could not use the bill pay feature. The workaround fixed this, thankfully.

  11. “The one area I had some trouble with Pale Moon is that some websites would not initially work with it, stating something like “you are using an old versions of Firefox”. Thankfully, there is a workaround for it, but it did take a little research to resolve conflicts.”

    Brad. May I ask what the solution was. please?

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