How to get Mail to recognise correct account?

Question

I changed ISPs about 3 months ago and got a new email address.
I keep both my old and new accounts as I still have mail being forwarded from the old account.
In Mail > Preferences> Accounts I have the current account above the older one and everything seems set up correctly. It is also correct in my Network settings and my Address Book.
However whenever I send an email it defaults to the old address as the sendee.
How can I fix this and what is the logic behind Mail's behaviour which has always had me puzzled?

Answer 1

You mean the new one is imap, right? smtp is for sending mail, pop and imap for receiving. Both pop and imap style accounts use smtp for sending.
OK so, you are correct, you don't want to delete the old pop mail account because you will lose all your old email.
However, have you tried deleting just the old smtp server information from Preferences | Accounts | {old account} | Account Information | Outgoing Mail Server pulldown menu | Edit Server List? If the outgoing mail server information no longer exists on your computer, then you shouldn't be able to send mail through that server. Then just specify the new account's smtp server for outgoing mail for the old account. (However, be advised that you should specify your new email address in the old account, which you probably want to do anyways, and differentiate between the two accounts by the "Description" fields in each account's Account Information panel. OR, specify "None" for the outgoing server. (That may have the undesirable effect of messages hanging out in your oubox, though).
As an unrelated side note, I know you can do this with imap accounts, and that is to drag messages from one imap account's inbox to another imap account's inbox. But I don't have any pop accounts so don't know if you can do a drag and drop from the pop messages stored locally on your computer into an imap inbox, where the messages are stored on a remote server (and optionally, off-line copies maintained locally on your computer. But, like I said, remote imap to another remote imap? No problem. Maybe you could give that a try with an old popmail message or two, that you could afford to lose, and see what happens...
To answer your Windows comparison question, I've not ever experienced these kinds of Mail problems on my Mac.