hi gary, sorry for this mishap! mozilla is considering in which way the problem should be addressed for users on legacy versions at the moment.

this would be an unofficial workaround i can offer in the meantime (basically the same steps that the automated hotfix was performing in the still supported versions of the browser):

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(1) Download the fixed certificate

The updated necessary certificate is available for download at https://hg.mozilla.org/releases/mozilla-release/raw-file/tip/security/apps/addons-public-intermediate.crt

Go to the Options/Preferences page, Advanced section, Certificates panel, then click Certificate Manager. Make sure the Authorities tab is selected, then click Import. Find the file you downloaded and open it, then you should get a dialog - don't check any of the boxes, just click OK. Then you should see the new cert in the list in the Certificate Manager, as shown in Screenshot #1.

(2) Clear the time Firefox last re-verified

This will set Firefox up to check much sooner than it otherwise would check.

(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

Screenshot #2 illustrates the expected result.

(3) Restart Firefox

You can exit Firefox normally, then start it up again. It should take a few seconds, but then your addons should turn back into an active state

Hopefully that will work for you.

That didn't work. Is there an estimated date for the fix for this vista operating system? And how will I know it's been fixed?

hi, the work to ship the addon certificate fix for legacy versions of firefox is tracked in https://bugzilla.mozilla.org/show_bug.cgi?id=1549604, it seems like they are making progress there recently, so i'd estimate this might start rolling out within 1-2 days. once the fix reaches your system, your installed addons should just turn active again and work as before this mishap.

That didn't work. Do you know when a permanent fix will be? And how will I know the problem has been fixed?