How to get my yahoo mail updated in macbook air?

How are you accessing Yahoo Mail--via their web interface or do you have access via Mail?

If the web interface that should be under Yahoo's control, which would suggest the password you are entering is not the password Yahoo has. Alternatively (but highly unlikely), it might be something in the cahce or cookies for the browser you are using on this Mac.

A way to test this would be to use a different browser temporarily to access Yahoo mail. To isolate things I might try that first on the machine that right now *has* access. It's possible you might have entered a new password and then had an error in copying it down. In that case Yahoo could very well work just fine in that browser, as it would have remembered the "wrong" password and, if you allowed the browser to store passwords, is offering it up each time Yahoo asks for the password.

If you download another browser (Firefox or Chrome if you are using the browsers that shipped with either computer) and then try to access Yahoo Mail on the machine which you believe is working right that should flag things. One strong hint--DO NOT allow the new browser to import passwords from the old one if it offers, since obviously if it pulls that one off it won't prove anything.

While you could accomplish the same thing by typing (not just accepting what the browser fills in) the password you believe is right into the browser on the working computer after logging out, but depending on how you handle that the browser might "forget" the remembered password that Yahoo thinks is right. That would potentially lock you out there as well, so another browser should be a safer way to isolate this issue.

If that is the problem you may be able to get the password from the "working" browser. If so, you'd need to tell us what browser you are using (Safari, Internet Explorer, Firefox, Chrome, etc.) and on what operating system (Mac OSX or Windows). Often there is a way to get the browser to give you (in plain text) the passwords it has remembered for you.

You could also try a different browser on the Mac that won't log in. If Firefox or Chrome also fail that would rule out a problem with Safari or that computer (neither one is going to care what Safari is doing) and point to a more general problem getting into Yahoo on other computers. If they do get in, then we begin to look into what Safari might be retaining on that Mac that is causing the problem.

You can download Firefox by going to:

http://www.getfirefox.com

Chrome can be downloaded from:

http://www.google.com/chrome

Unfortunately I've found that Mail tends to initially diagnose every problem as a password error :-), so that may or may not be the issue.

On the chance it is the error, try retrieving your Yahoo password that Safari is using from the keychain. To do so, go to your Utilities folder in Applications in Finder and fire up the Keychain Utility. Using it, search for the login.yahoo entry:

If you click the entry in the window you'll get this dialog which will allow you, if you check the box and give your keychain password, the password that Safari is using. You can select it and press Command-C to copy it to the clipboard.

If you accidentally change it *don't* press Save Changes (actually don't do that anyway :-) ), but simply use the red button in the upper left corner to close the window. You can then paste that password into Mail and see if that solves the issue. That might happen if, for instance, you hadn't noticed CAPS LOCK was on when you changed your Yahoo password, or you managed to make the same typo twice (I've done that one before) when confirming the new password.

If that's not the issue, then you need to try and figure out Yahoo's real complaint back to Mail when it tries to log in. You can use the Connection Doctor in Mail for this. You'll find it in the Window menu.

It will run intially and provide some more detail on the problem. However, you can also turn on "Show Detail" and have it Check Again if the first run doesn't clarify matters. The Show Detail will give you the details that Mail sent and, more importantly, what the server at Yahoo sent back. Often there may be some text in that return message might tell you what the issue is.

That said, I know Google implemented optional 2 factor authentication systems for Gmail. If Yahoo did the same and you became part of that there may be additional steps to "verify" to Yahoo that Mail is truly authorized to access your mail, since presumably you changed your password because of concern it may have been compromised (so it's going to force every connection to "prove" it is authorized to access). If that is so, you may need to complete whatever secondary system Yahoo might be using. With Gmail you have to generate a new Mail specific password to be used.