The same happened to me. I'm on an iMac desktop. Bookmarks and history are empty, including the toolbar for most commonly used sites. Wondering how I can retrieve them as I had probably at least a hundred. I also don't seem to be able to add a new bookmark. I followed instructions from earlier posts about missing bookmarks, to restore them. It did not work. I'm stumped. I quit out of Firefox and restarted it. Weird/magically the bookmarks came back. Don't know why I didn't try that first.