I had quite a few add-ons installed and I have been using them for a while. Today FF noticed me of an update and I updated it to latest version (64.0.2), but after restarting the FF all my add-ons are missing. I am using FF in Windows 10. Nothing listed anymore under "about:addons". The most important one that I have been using extensively was "Tab-Session-Manager" which is missing and I am loosing a large number of windows I have saved there. Is there anyway to re-enable the add-ons, or recover those stored sessions? Thanks.