Update: a partial fix has been shipped by Mozilla
A few hours ago a security certificate that Mozilla used to sign Firefox add-ons expired. What this means is that every add-on signed by that certificate, which seems to be nearly all of them, will now be automatically disabled by Firefox as security measure.
In simpler terms, Firefox doesn’t trust any add-ons right now.
Basically, all your Firefox extensions will be disabled and won’t work until Mozilla fixes this embarrassing issue. Until they do, you can go to
about:config and set
false. This is obviously a major security issue, so only change this flag if you know what you’re doing, and don’t forget to set it back to
true once Mozilla fixes the issue.