I bought a new desktop PC with Win 8.1 and installed Firefox and Thunderbird. Then, I tried to configure the e-mail account manually (as IMAP) following the instructions provided here: https://support-en.upc-cablecom.ch/app/answers/detail/a_id/22 , but failed to configure the smtp outgoing mail server correctly (I could receive mail, but not send them). Subsequently, I deleted that account. Then, I launched the automatic mail setting tool provided by UPC Cablecom under the link http://www.upc-cablecom.ch/content/dam/www-upc-cablecom-ch/Support/executables/upc-cablecom-email-assistent.exe and it did successfully setup the account, however as a POP3 account. As I was not happy with it, I deleted the POP3 incoming mail server (and lost the received e-mails, of course...) and retried a manual setup. Doing so, I obtained an incoming IMAP mail account plus two outgoing SMTP server (comparing them, I also understood the configuration mistake I had done the first time). I then deleted the manual SMTP server as the automatically setup server worked properly. In this context, both receiving and sending e-mail worked OK. However, the next time I started the computer, the e-mail account disappeared and Thunderbird asked me to setup a new account again. I successfully set it up manually one more time, but the same problem surfaced again at the next boot, the e-mail account was gone...! Thanks in advance for your help! Maxonce