You wrote that I could override the machine key. Can you tell me more about it? Does it mean that if I upgrade the way I described, all other users of my forum will also have login problems like me? Is there a related documentation I can read?
BTW, when I upgrade the way I do, I never change any specific setting in the forum .config files. I imply that this machine key is something related to the web-server (server name, OS version, something else) and not a thing coded in the .config files. With that said, I simply can't change this machine key with my actions!
As for the security question, ok, I understand that they are saved in a coded form in the db. However, if I have access to my account and can change almost anything in my profile, why can't I change the security question?? I would be glad if I could overwrite it with a new question/answer pair. Is it possible?