My PC was running windows 8 and done an automatic update to windows 10. Everything was fine and Mozilla was still on my PC but everything in my inbox was gone. I had lots of sub folders within my inbox and everything has completely disappeared. I don't have a back up server and I have been told that they are backed up somewhere on my PC but I don't know how to find them. It has also deleted my entire address book which is very important as well as I have no other way of getting all of those e-mail addresses. Has anyone had this problem or know how I can revert back to how it was and gain access back to all of my e-mails?