Did you lose a bunch of add-ons? That could happen if you used Firefox's Refresh feature. This could occur when Firefox reports that it is running slowly and you can speed it up by restoring default settings. And then an Old Firefox Data folder appears on your desktop. Do you see anything like that? It's not very straightforward researching old add-ons in the Old Firefox Data folder, but it's possible. Before diving into that, if relevant, I notice you have numerous RealDownloader plugins. Can you check whether they are fully enabled? You can do that on the Add-ons page. Either: * Ctrl+Shift+a * "3-bar" menu button (or Tools menu) > Add-ons In the left column, click Plugins. For RealDownloader plugins that seem relevant to Firefox, change their permission to "Always Activate" if they are set to "Ask to Activate". For those that do NOT seem relevant to Firefox (Chrome and PepperFlash), I would set those to "Never Activate". These kinds of changes often do not take effect in the same window. Try opening a new window (Ctrl+n) and visiting a site where RealDownloader is supposed to activate to see whether it does.