I fail entirely to see any reason for even suggesting that. I am aware of SMTP servers that require a login to the POP or IMAP server before they will send mail, very rare and usually used as the entire authentication to send mail.

That said I really fail to understand what it is you are suggesting. How would Thunderbird logging into the server fix your issue? Given that each SMTP send session (which is designed to delver mail) ends with a logout process. How does your backup program send it's mail? Generally they either use MAPI, which leaves the mail open waiting for you to click send, or they use SMTP, requiring your to set up the password and user name in the program so it can login and access the SMTP server to send mail.

If I start Thunderbird it asks me for a password. I supply it then it will download new emails from Hotmail.com and continue to do that without requesting a password. Now If I send a email or reply to an existing email It asks me for the password for the SMTP Server and the email is sent. after supplying the password. Now if I send another email it gets sent without requesting the server password. It would seem that Thunderbird remembers the passwords. Both the POP download server password and the SMTP outgoing server password. Thunderbird is set as my default mail application. I had restarted Thunderbird and received the new Hotmail emails but did not need to send any emails before the backup program attempted to send an email.

Can I ask why you do not just save the hotmail password in Thunderbird. I have been doing it for years. It is not as if someone else has access. Not if your operating system local account is secured properly. (don't bother even with that. I should set a windows password, but I have been remiss for months on the topic after having one since Windows 2000.)

I an not aware of any way too permanently save the passwords when Thunderbird is closed for what ever reason, usually a shutdown or restart. When I restart Thunderbird it asks me for the passwords for both my Hotmail and ISP mail download passwords. The next time I send an email I am asked for the server password. The passwords are remembered as long as Thunderbird is not shut down at which point the password request sequence begins again when I restart Thunderbird. If I search the Config file with Pass nothing looks like it would force a password save at shutdown. I cannot find any documentation on what the items in the config file actually do.