I was not aware Thunderbird imported anything from apple mail. This bug with the manual process described would indicate that to be the case. https://bugzilla.mozilla.org/show_bug.cgi?id=688166#c23

As far as Thunderbird recognizing your ISPs password, would it be ATT by any chance? The yahoo outreach program that requires you use something else called a mailkey instead of your password? Or are you arriving at this post update when it may well be an anti virus product installed on your system. They are somewhat notorious for messing up account creation in Thunderbird with their helpful blocking of the account probes and firewalls that block connection to the internet post update..

Under System Requirements it does show Mac OS versions up to the current one. So it seems reasonable that Tbird's Wizard would be able to import from Apple's Mail. But, as you mentioned, providing a manual process would indicate that the wizard wouldn't work. Unfortunately even the manual process doesn't work either. This bug goes back years from what I could see online so I was thinking it would have been solved by now, but apparently no.

My ISP is Hawaiiantel. I'm not using an external antivirus, so that's not the cause.

I'm getting a good 50 spams a day and was hoping changing emails would solve the problem as when I used Tbird before I had far fewer. I guess I'll have to try something else.

thanks for your two cents.

Under System Requirements it does show Mac OS versions up to the current one.

That is because the product runs on that system, not that it does anything else on that version of software.

So it seems reasonable that Tbird's Wizard would be able to import from Apple's Mail. But, as you mentioned, providing a manual process would indicate that the wizard wouldn't work. Unfortunately even the manual process doesn't work either. This bug goes back years from what I could see online so I was thinking it would have been solved by now, but apparently no.

Apple represent less than four percent of Thunderbird users. So despite the age of the bug, I do not see large amounts of money being put into importing from apples product as few of those will be importing from apple mail. The prevalence of IMAP and server storage almost makes importing for other mail products obsolete. Most folk have full copies on the mail server that will be downloaded when the account is configured. In the last 10 years I have seen the range of import options shrink, not grow.

As for the manual process which part of it do you have trouble with? If it involves apple mail that I can not help you. I do not pay extra for apple. If it is something about the import then perhaps I can assist.

My ISP is Hawaiiantel. I'm not using an external antivirus, so that's not the cause.

Well after jumping through hoops and a very poorly laid out web site I lean that your provider have basically not updated their security singe 2000. https://www.hawaiiantel.com/Residential/Support/Support-Articles/email-account-settings

Based on the dearth of information they supply there, I would assume the connection security is none and the ports will be the old defaults of 110 for pop, 25 for SMTP and 143 for IMAP. Each of those would have the authentication method set to normal password.

I'm getting a good 50 spams a day and was hoping changing emails would solve the problem as when I used Tbird before I had far fewer. I guess I'll have to try something else. thanks for your two cents.

Changing mail clients is not going to help you with getting less spam as the spam does not originate in the mail client. While apple mail might allow more recognition of you opening the mails by downloading remote images which Thunderbird does not by default, which does allow tracking and reporting that would be about the only difference. Most spam for US citizens comes from aggressive marketing practices that are not allowed in the rest of the world, so perhaps the issue is regulatory not technical at all. Here in Australia I have to sign up for marketing mails. If some company just send them out they can be fined hundreds of thousands of dollars per email. Guess what. We don't have a US style problem with spam. We get the scam stuff but I get perhaps 5 emails a week in my inbox that go to spam. Mostly actual scams. and my provider is good at making legit mail a false positive (Good one Google)