Ive used Firefox for years, but in a recient update, Firefox Quantum, disabled all of my Firefox addons. The addon page in Firefox shows a link to a Firefox help page that states the reason. "Only extensions built using WebExtensions APIs will work. ." At the bottom of the page it gives a work around. Set; xpinstall.signatures.required to false in about:config. I was able to reinstall one addon, Video DownloadHelper, but the rest I try to reinstall gives me a message in a red box, Download failed. Please check your connection. Is there something else I can do before I try a different browser?

@Gerowen, The link is usefull although I had already uninstalled my addons. After enabling studies, it didn't change my firefox , it shows no active studies, and I'm unable to download addons. It's good to know that the issue is being addressed though.

update...I made xpinstall.signatures.required false in about:config, and enabled studies Allow Firefox to install and run studies in Preferences/Privacy and Security settings section. In about an hour the bugfix showed up in View Firefox studies link, so Mozilla is fixing this. http://tinypic.com/r/35clncx/9 I reinstalled the addons, re-enabled xpinstall.signatures.required, and unchecked Allow Firefox to install and run studies, and Allow Firefox to send technical and interaction data to Mozilla. All of my addons seem to be working properly.

I ran into same issue on a laptop with Firefox, and was able to receive the hotfixes from mozilla without modifying xpinstall.signatures.required value.

Dell Optiplex 7040, Ubuntu 18.1, Firefox 66.0.3 (64-bit)


This has been acknowledged by Mozilla, and a fix has been released as a "study" that should automatically install itself if you have them enabled in Firefox's settings.

Here's the blog post discussing the issue and the fix:


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    I just ran accross this site. phoronix.com/… – joeRag May 5 at 1:10
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    It took about an hour for the study/s to show up. tinypic.com/r/35clncx/9 – joeRag May 5 at 2:14
  • Funny thing, my "DuckDuckGo Privacy Essentials" addon was still borked. I could enable it and whatnot, but after this incident it blocks all internet traffic within Firefox and no longer functions properly, :-( – Gerowen May 5 at 2:51
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    I don't like the way I have to enable Allow Firefox to send technical and interaction data to Mozilla. I always disabled this in the past. It contradicts anonymity. – joeRag May 5 at 3:14
  • This solution was good but is now obsolete because it is now enough to make sure your Firefox is up to date. – geras May 10 at 15:22

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