Sounds like corruption, of either the Hard Drive or the Keychain.
See if this helps...
Open Keychain Access in Utilities, use Keychain First Aid under the Window Menu item, then either check the Password under that item, change it, or delete it and start over.
Resetting your keychain in Mac OS X...
If Keychain First Aid finds an issue that it cannot repair, or if you do not know your keychain password, you may need to reset your keychain.
Keychain is no longer able to update itself when I upgrade an application...
i had the same exact problem for the last few days. I did the keychain reset as BDAqua suggested might help, but it did not resolve the problem for me. I called AT&T (the internet provider) and they suggested changing the password to something totally different. I'm not sure if they did a reset on their end, because they gave me a temporary password and then stayed on the line while I then went to the AT&T site and changed the password to one of my choosing and then went into Mail prefs and changed it under account setting too.
So far, I haven't had the window come up... fingers crossed. He said this usually resolves the issue.
Maybe this helps.
Still haven't tried the suggestions, have been away from 'puter all day. Appreciate all info, though. The odd thing is this has happened before, for a time, and it has eventually gone away without me doing anything I'm actually aware of to resolve it. So this time, I thought I might try to actually figure it out. I'm having second thoughts about THAT strategy! But if it keeps doing it I probably will try something...will report back later, thanks all for responses...
I just dug up an old email from AT&T from the last time this happened to me awhile back... I think it's still relevant, even though I don't think they'd admit to this now.
here's part of it:
"In using the Mac Mail, the reason why that a pop up dialog box keeps on appearing every 2 - 30 minutes is because of a network event detected. This network event states that customers are prompted for their password when using POP clients, such as Microsoft Outlook, Mac Mail for email. Unfortunately, there is currently no Estimated Time of Restoral (ETR).
To access your Mail, you may use the AT&T Web mail. Please do the following:
1. Open your browser [Safari or Firefox] and in the address bar insert the address http://sbc.yahoo.com.
2. Insert your member ID [email@example.com] and password.
3. Click on the [Mail] icon.
If you did not encounter the issue using the web mail, you may need to recreate your e-mail account on your Mac Mail. Please follow the steps below:
1. From the Mac Mail toolbar click [Mail].
2. Select the [Preferences] option. The Account window will appear.
3. Click on the [+ (plus)] button on the bottom-left corner of the Accounts window. The New Account wizard window will appear.
4. Select the [Continue] button to launch the email configuration walk-through.
5. Select [POP] as the Account Type from the [General Information] screen and enter the following information before selecting [Continue].
[Account Description]: Give an Account name.
[Full Name:] Your Name
[Email Address:] Email address of account being configured
6. Enter the following information on the Incoming Mail Server screen and select
Incoming Mail Server
User Name: This should be the complete e-mail address
7. From the [Incoming Mail Security] screen, verify the following before selecting [Continue]:
8. There is not a check mark in the [Use Secure Sockets Layer(SSL)] box.
[Password] is selected from the Authentication dropdown selection.
9. From the Outgoing Mail Server screen, enter the following information before selecting [Continue] (ensure the Use Authentication box is checked):
Outgoing Mail Server
User Name (Complete email address)
10. From the [Outgoing Mail Security] screen, verify the following before selecting [Continue]:
Password is selected from the Authentication drop-down.
The Secure Sockets Layer (SSL) box is not checked.
Screenshot: Outgoing Mail Security
11. From the Account Summary screen, verify the information then select [Continue].
12. Select [Done] when the [Conclusion] screen appears to exit the wizard.
If after recreating the account and still you encounter the problem, you may need to have your Mac Mail client to be checked. Unfortunately, AT&T does not configure third party e-mail clients. You may need to call AT&T Support + or your Original Equipment Manufacturer, Apple. AT&T Support + is a fee-based technical support service that would be glad to assist you. You can reach AT&T Support + at 1-866-294-3464 or Apple at 800-767-2775."
(numbers might be different now)
Anyway, I think this is pretty much why, at least for my situation... and that's why it comes and goes away on it's own, because they're working on their servers, or some such. I think right now, AT&T are doing major work with their internet, u-verse, etc so it would make sense that some of us are experiencing these drops at this time, plus whatever issues Mac Mail contributes. So that's my 2 cents.
have a great day.
Message was edited by: Sulimo
From time to time this has happened in the past with AT&T internet users. For the past couple of weeks I've been experiencing email server problems too, but so far, mine have just been with the outgoing email server, not the incoming which is usually the case for me. After going through this stuff intermittently for years, a user on the AT&T internet forums sent me an IM saying it was the server I was having problems with and sent me the addy for his server which was different than mine. He was using a server on the West Coast and I was using one here in the Midwest. As soon as I switched to his server my email problems vanished.
In the past it has usually been Outlook and Mac Mail customers who have been bothered but so far (this time) I'm only noticing Mac users having problems. There used to be a LOT more complaints about this in previous years but many folks switched to some other email account after getting fed up with AT&T. If this goes the same way as it has in previous years, it will just continue to get worse until a whole lot more folks complain and then AT&T/Yahoo does something about it.
I'm using my regular Mac Apple Mail program and live in the St. Louis area.
I get this periodically, and am not an AT&T user. It seems to happen when I have 2 computers on and have my mail programs running on both, Outlook on one, and Mac mail on the other. I think it happens if one is trying to get email while the other one is and it gets bounced out. I just close the box that says to re-enter the password and go to my mac mail window and click on the "go online" button next to the inbox and it seems to reconnect. If it doesn't, i just close the whole mail program and reopen and it seems OK. that window that asks you to re-enter your password goes nowhere, it's a never ending circle.