Seems like this is an old thread, but I'm experiencing this exact issue. Started about 1 month ago ... EN starts up, and within a couple of minutes, consumes 25% of my CPU. I've uninstalled and re-installed, and I've disabled the FireFox EN plug-in. Still, 25% CPU usage. Fan continually runs on my laptop. If I use Task Manager to stop EN, then my CPU usage returns to normal, and the fan stops. I've reviewed the activity log and nothing really stands out. Maybe resurrecting this thread isn't correct. I'm open to start a new thread.