Post of the month nominee for sure! I too have scoured the forums and tried to get it Yahoo Mail into Apple Mail to no avail. Thanks! For the record, works without Plus access and also on 10.6.5 and Mail 4.4 (1082)

Select the Apple menu, then select System Preferences. Select Internet Accounts. Enter your Yahoo! Email address and select Next. Enter your Yahoo! Password, and select Next. MacOS will ask what aspects of your Yahoo account you'd like to use. Leave everything checked, and select Done. Yahoo makes it easy to enjoy what matters most in your world. Best in class Yahoo Mail, breaking local, national and global news, finance, sports, music, movies and more. You get more out of the web, you get more out of life. Account has now been added to your Mac. Account will now be accessible via any of the apps you selected. For example, if you checked Mail, Calendar, and Contacts, your Yahoo! Email, calendar data, and contact information will be synced with the corresponding Mac apps. In the Mail app on your Mac, choose Mail Accounts. Select the account, then deselect the Mail checkbox. Now the account’s messages are not shown in Mail. To use the account again with Mail, select the Mail checkbox; the account’s messages are shown.

Having just used this hint to set up my Ymail account in the latest version of Mail & 10.6.6, I can confirm that a Plus account is NOT required for this to work! VERY cool indeed!! I've been telling folks for years that a Plus account is required to use a Yahoo account in Mail.app. I'm so psyched to learn that it's no longer the case....

This doesn't work for me
(10.6.6/Mail Version 4.4 (1082) as specified))
When I fill in my Yahoo Plus email address and the incorrect password I get a warning:
'The account “Yahoo” already has this host name and user name.' and not the results predicted in the hint.
The 'Continue' button does nothing.

wow, works great !
great hint , thanx !

Thanks Steve! My Yahoo! account was falling into disuse, because of the lack of IMAP.
You can set up the connection manually quite easily, The other item to note is that (if you have a Yahoo account from another country) the servers are still just '.com' rather than '.com.au' (in the case of Australia).

Fantastic. Thank you very much for the detailed description.

This worked (mostly) for me. Thanks.
Fetching and sending work fine as do my folders. Now I'm trying to set up drafts/sent. I'd like to have my drafts/sent stored on the server. When I ticked the boxes in settings, it created new folders instead of using the ones that Yahoo already has. When I told mail to use the folders that yahoo has, it didn't work properly, i.e., things didn't stay in sync.
Has anyone set up drafts/sent on server for yahoo Imap? If so, how did you do it?

I had a similar problem too but it was a matter of prefs and settings in the webmail version...

Did you manage to make it work? If so, what settings did you use?

Best Hint in a Long Time Works Like a charm! Thanks

What a delight. I struggled with this a few months ago, Yahoo were polite but no help. Works as others have said without a Plus account. I'm in UK and used the .com settings.Thanks Steve.

Thanks so much, fantastic.

I have a question. I currently have yahoo account in mail.app configured to use pop. What is the correct way of changing it to imap? Should I delete my current setup? Should I add new account then once its synced, delete my pop account?
thanks

I, too, already had a Yahoo Plus POP account. I was able to successfully set up the IMAP, but should I now delete the POP? Is there a way to merge them? The POP has way more Yahoo messages in the inbox than the IMAP, so the IMAP must only be taking over what is currently on my server (I must've accidentally deleted original server messages when first creating the POP - so I need to save those messages!)

Warning : If you delete a POP account from Apple Mail it will delete all your email.
You should start uploading your mail from POP account into IMAP account. Do it bit by bit as it can bum out.
Once done i would backup your POP account ~/Library/Mail, then remove.

Thanks for the tip

Thank you so much for this brilliant hint. It must have taken a lot of trial-and-error attempts.
I have only a regular Yahoo! email account. And, I just followed this hint step-by-step and everything works perfectly now in Mail.app 4.5 (1084) under OS 10.6.7. I never thought it would be possible to manage my regular Yahoo! account in Mail.app until today.
Thanks again.

Sweet, nice one. Works for my standard account on 10.6.7 and Mail 4.5 (1084)
Many thanks.

Fantastic!
I was really skeptical seeing that port 995 there on the final screen of the setup wizard in Apple Mail, but thought 'what the heck, Apple will know which port to use, Yahoo! is supported after all.'. How wrong I was. Now it works perfectly.
Thanks a lot for a great hint.

I am running OS 10.7 Lion on a 2011 MacBook Pro.
Even after I upgraded to Lion a couple of days ago, this whole thing was working in Mail.app. But, as of July 23, 2011, it stopped working. I wonder if other people have run into this issue.

Nope... mine also stopped working in the last couple days... receiving this error:
'cannot send message using the server smtp.me.com' and 'the server 'smtp.mail.yahoo.com' cannot be contacted on port 465... Select a different outgoing mail server'

Yep, mine also stopped working...Yahoo introduced there new mail system online from memory...they must have changed something?

This didnt work for me..help pls!
Version 4.5 (1084)

Yahoo Mail Download

Here are the IMAP settings in one place, works for Apple Mail and iOS with Yahoo and Yahoo Plus mail, also works with Win7-Outlook 2010.
To set up IMAP on Yahoo and Yahoo Plus use these settings:
Incoming Server - imap.mail.yahoo.com
Outgoing Server - smtp.mail.yahoo.com
Incoming Port - 993 (requires SSL)
Outgoing Port - 465 (requires SSL/TLS)
Username: full email address (for example, bill@yahoo.com or bill@rocketmail.com)
Password: the password you login to Yahoo! with.

I love this! Thank you so much! The Yahoo interface is so annoying and now I don't have to deal with it any more!!! Thanks again!

Yahoo Free Download For Laptop

I tried the method in this comment, but it did not allow me to add the same user account, and click Continue, as suggested. Then I realized the set up was for Mail Plus accounts. In further troubleshooting tips, I found out that the easiest thing to do to avoid signing up for Yahoo! Mail Plus,was to go into your usual Yahoo! Mail account in Webmail, and be sure you are in CLASSIC mode, rather than the new YMail version. Then go to your Mail app (on your Mac (OS X Lion),Quit it, reopen it, and click on Get Mail. It should load all of your mail. Yahoo!!!