We rolled-out a fix for release, beta and nightly users on Desktop. The fix will be automatically applied in the background within the next few hours, you don’t need to take active steps.

In order to be able to provide this fix on short notice, we are using the Studies system. You can check if you have studies enabled by going to Firefox Preferences -> Privacy & Security -> Allow Firefox to install and run studies.

You can disable studies again after your add-ons have been re-enabled.

Please do not delete your add-ons as an attempt to fix. You will lose any data related to the add-on. Disabled add-ons will not lose any data.

There is no fix available for Android at this time. The team is working on it.

We are working on a general fix that doesn’t need to rely on this and will keep you updated.

Hi Dqu1J, there probably is not problem with the Add-ons themselves. There is a more general problem with verifying that add-ons were validly signed by Mozilla. A fix is being distributed for that, as described in this article:

Add-ons disabled or fail to install on Firefox

Could you review that article and see whether your Firefox is set up to receive the patch(es)?

Also, if there are particular extensions you have a question about that do not get re-enabled, please let us know.

Dqu1J said

Can i somehow use outdated plugins for firefox? I need this too much.

You likely mean Extensions as a Plugin refers to say the Flash Player Plugin (NPAPI) from Adobe.