After a recent automatic update to Firefox version 43, I found that one of my favorite extensions, download manager DownThemAll!, had been automatically disabled because it was unsigned. This is the default behavior in Firefox 43 and above, and if you’re reading this, you’ve probably had a similar problem.
Fortunately, it’s simple to get these extensions working again. Just type
about:config in the address bar, click through the warning, and then search for
xpinstall.signatures.required. Double click that config entry when you’ve found it, and it will change the value to
Quit and restart Firefox, and your disabled extensions should work again. Here’s the thread where I found the solution.
Hopefully, this workaround will remain available in future versions. But there’s still bad news on the horizon. DownThemAll! reports that XUL-based add-ons will be deprecated in the next year or two, which would limit what Firefox extensions can do. Currently something like DownThemAll! is impossible in Chrome, and it may become impossible in Firefox, too. Fingers crossed that there’s a change of course.