I don't think forum volunteers yet know the cause or remedy for this problem. However, know that dozens of people are reporting the same thing in recent hours, so it may be due to a rolling update gone wrong.

Yeah, might be, considering the "obfuscated code" thing

Actually, it looks like a certificate used to sign many popular extensions expired. Whoever wasn't keeping track of that is probably having a very bad night.

Makes sense. Hopefully they fix it soon

I had this problem too, and looking for a solution found one that was similar, which said to uninstall and reboot the machine and reinstall, which I did, and now, none of the disabled add-ons are listed in my Add-ons Manager. I'm hoping there's some way to be able to retreive them as well.

Hi dburns7, did your uninstall lose any other data, or just the extensions? One the heat of the crisis has passed, could you start a new thread with your system info (e.g., Windows 10, MacOS, etc.)? We may need to help you dig up a backup.

Some of my customization was gone, but I think that's normal if you uninstall and reinstall. (I recently moved to a new computer and even though I used Sync, the customization wasn't there). All of my bookmarks were where they were supposed to be.

Same problem here: all but one add-ons have all been disabled (most of them are security add-ons!) and cannot download new versions, plus some of my customizations have changed --my tabs are all black(!?).

Restarting Firefox changes nothing.

Odd and alarming that this happened in the background while I wasn't even using Firefox, since I've set it to not update automatically.

Hi Pitsligo, it wasn't an update. A critical Add-on-related certificate expired (which obviously should not happen). As a result, all verifications for that certificate are failing. This affects using, updating, and installing affected extensions.

The Add-ons team is working on a fix for this. Official updates are expected to be posted here:

https://discourse.mozilla.org/t/certificate-issue-causing-add-ons-to-be-disabled-or-fail-to-install/39047

Currently, the only workaround is to set your system clock back (for example, if your date is May 3, set to May 2; if your date is May 4, set to May 3). You might have to reinstall extensions after that, or maybe Firefox will detect the difference at your next shut down/restart. Changing the date may have other consequences, so I understand this option isn't ideal.

Mozilla has rolled-out a fix for this. 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, they are using the Studies system. You can check if you have studies enabled

1. Go to [=] > Options > Privacy & Security.
2. Make sure Allow Firefox to install and run studies is check marked.

I you had it disabled, you can disable studies again after your add-ons have been re-enabled.

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