Firefox ESR 45.2.0 Linux (Lubuntu) Everytime I open FF, it stalls while trying to connect to a URL, which works out to us-west-2.compute.amazonaws.com. This behavior doesn't happen in Safe Mode, so it appears to be related to extensions. Here is what I've tried to stop this behavior: 1. Disabled application and search engine updates 3. Get Add-Ons Page > Unchecked "Update Add-ons Automatically". Clicked on "Reset All Extensions to Update Manually" Result: No change in behavior. FWIW, while unchecking the first box clearly showed an unchecked box, clicking the "reset ...manually" link didn't result in any visual change indicating that it had taken. 3. Tools > Add-ons > Extensions > "More" (for each extension) > Automatic Updates to OFF Result: None of the changes stick. They revert to DEFAULT 4. Searched for "update" in about:config and changed every entry relating to updating extensions to FALSE 5. Searched for "update" in about:config and changed every link related to extension updates to 127.0.0.1 6. Put the offending URL/host in my hosts file, tying it to 127.0.0.1. Hosts files don't support https apparently, which I guess is why this doesn't work. Nothing works. I would have thought #2 and #3 would work, but they don't