So ... I posted about this problem a few weeks ago: (https://support.mozilla.org/en-US/questions/1144546), and it seemed to not be resolved. I then switched to Chrome - liked a LOT about Chrome; how smooth and fast everything moved. But, there were severe limitations (that impacted the way I use my browser); and I believe I have little option but to return to Firefox. I downloaded the very newest Firefox 50.0.2, as well as Palemoon, Waterfox and Cyberfox. I imported my bookmarks into each of those (and each time, the same problem occurred as in my original thread. The resource monitor would show the application in red with "not responding." This time, however, I began receiving "unresponsive script errors" (which happened infrequently before) -- like this one: Script: chrome://browser/content/places/editBookmarkOverlay.js:1116 And, of course, while that's happening, I can do nothing else. So far, I'm tracking each of the browsers (except I can't run Waterfox and Firefox simultaneously) -- and it looks like Palemoon uses the least CPU for similar tasks. However, *all* of them work poorly, for example, on LinkedIn, when replying to messages (I wish there was a way to video the experience for here). Basically, after hitting "reply" the entire message box flashes sporadically, and my typing is delayed significantly. So far, the normal 6-10 times an hour of freezing hasn't seemed to happen -- then again, these are all fresh new installs (I even uninstalled and deleted Firefox before reinstalling it), and -- so far -- there are no extensions added. I'd just love to know what I can do to offset this issue, before I begin customizing and reloading extensions (into whichever of the four engines I finally decide upon).