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