When I started Firefox today, there was a new tab with some information about something or other I have completely forgotten, as I soon discovered all of my bookmarks were gone, which is the only thing I can think about right now. I easily found advice about how to switch to another profile that might contain my missing bookmarks, but I have only one profile listed, the default one. I also easily found advice about how to go to the Library and import a backup. I can get as far as clicking "Choose File," but after I do that, absolutely nothing happens, no matter how long I wait.