why do my new emails disappear from my Inbox
I just set up Mozilla Thunderbird (because of a horrendous experience with Windows Live Mail), and it's just as bad if not worse. I got a couple of mails in my Inbox and seconds later they vanished before I could even read them, and what's worse is that they aren't in the Trash or Junk folders. In the Options menu I selected to not delete any emails yet they still vanish. As I was typing this, a popup just notified me of a new email, but when I went to read it, the Inbox it's empty. Nothing personal, but wtf?!!!
Wšykne wótegrona (1)
More then likely you have another device that's setup to check your e-mail and delete them from your server (like a phone/ipad). Go into the settings of all the other devices that check your mail and change their settings to IMAP and to leave a copy of e-mails on the server(not to delete after download).
If you can't track down all those devices, change your email password and they won't be able to login and delete them until you update their settings.