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.

jscher2000 said

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.

Yup, I saw those just after posting my own question, haha. At least I know it's not just me!

As an interim update: The Add-ons team is working on a fix for this. It looks like a certificate used to sign many popular extensions expired. (The verification process checks that certificate.)

I don't know how soon re-signed versions of those extensions will become available, or whether another workaround will be discovered. We are all hoping to learn more soon.

Looks like it's working again now.

See also:

• https://support.mozilla.org/en-US/kb/add-ons-disabled-or-fail-to-install-firefox
• https://blog.mozilla.org/addons/2019/05/04/update-regarding-add-ons-in-firefox/

I am using FF 60.6.1ESR and the problem persists in it. My system has Oracle Linux 6.5 (which is based on RedHat 6.5) and the latest version of FF supported by this OS is 60.6.1ESR.

karthikeyan.d said

I am using FF 60.6.1ESR and the problem persists in it. My system has Oracle Linux 6.5 (which is based on RedHat 6.5) and the latest version of FF supported by this OS is 60.6.1ESR.

The Mozilla blog says that a fix for the ESR version will be available soon :

  An update for ESR users will be available tomorrow. We’re also 
 working on a fix for older versions of Firefox, and will update 
 this post and on social media as we have more information. 
 (May 7, 15:37 EDT)
     - https://blog.mozilla.org/addons/2019/05/04/update-regarding-add-ons-in-firefox/

Note that the current is 60.6.2.

• https://www.mozilla.org/en-US/firefox/60.6.2/releasenotes/

cor-el said

Note that the current is 60.6.2.

• https://www.mozilla.org/en-US/firefox/60.6.2/releasenotes/

Yes. However, since the system is my office laptop I usually install using the official Yum repository which is yet to provide 60.6.2. Once the fix is available in a newer version I'll try it by downloading it directly from the FF web site.

This is happening to me again on Firefox version 69.

Hi powerllama, what does your Add-ons page, Extensions panel, show? For example:

• There is a message explaining that the extension could not be verified, either on the little tile or when you click the add-on name to view its detail page.

• There is no message or explanation, but there is no Enable button or the button is inoperable/disabled/grayed.

• Something else.

Multiple extensions with the "could not be verified" label. uBlock Origin, 1Password X, and Stylus. I can delete and redownload them from addons.mozilla.org but then I think I'll lose my Stylus CSS edits.

powerllama said

Multiple extensions with the "could not be verified" label.

Hmm, a frequently updated extension like uBlock Origin shouldn't have a problem any more. Are you on the current version (1.22.2) ?

Could you check your system clock to make sure it's not a problem with time travel? The certificate used for verification is valid between:

Friday, April 3, 2015 - Thursday, April 3, 2025

To trigger a re-verification sooner than the usual "every 24 hours," you can use this method to clear the time stamp for the last time Firefox last re-verified.

(A) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful or accepting the risk.

(B) In the search box above the list, type or paste xpi- and pause while the list is filtered

(C) Right-click the app.update.lastUpdateTime.xpi-signature-verification preference and click Reset on the context menu -- the numeric value will disappear and the preference will say it is now a "string".

The next time you exit and restart Firefox, the re-verification should be performed within about a minute.

Success?

You can try to start Firefox once with the '-purgecaches' command line parameter.

• https://developer.mozilla.org/en-US/Command_Line_Options

You can check for problems with the extensions registry files in the profile folder.

Try to to reset the extensions registry and rename extensions.json (extensionsOLD.json) and rename/remove previously used extensions files like extensions.ini and extensions.sqlite when present and rename/remove compatibility.ini in the Firefox profile folder with Firefox closed.

• https://support.mozilla.org/en-US/kb/Profiles

New files will be created when required.

See "Corrupt extension files":

• https://support.mozilla.org/en-US/kb/unable-install-add-ons-extensions-or-themes

You can check for possible updates in case of issues.

• click the cogwheel button (left of the Search bar) on the about:addons page to "Check for updates"

If this didn't help then rename/delete add-ons.json and possibly prefs.js in case there is a problem with preferences.

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/Profiles

Today, everything showed back up. Not sure what the hiccup was! I'll save these options for later if it happens again. Thanks for the help!