Tired of re-entering my password! Is there an alternative to MAIL?

Have you deleted your e-mail keychain entry in Keychain Access, relaunched Mail, and reentered it?

Like many of you,

I haven't seen much discussion of this, so I don't know how 'many' you mean, but still…

I don't think your problem is Mail.app - at least not directly.

What Mail.app is telling you is that it couldn't log in to your mail account. While it reports the password as being the problem, that isn't necessarily the case. If the mail account is locked then you'd get the same error - the login failed. Since Mail.app doesn't necessarily know why it failed it assumes it was a wrong password.

The reason why re-entering the password 'fixes' the problem is that by the time you type the password and click OK the lock has been removed and the mailbox is available.

So the question is why is the mailbox locked?

The most likely cause is that you have multiple devices checking into your mailbox - maybe your Mac, your iPhone, your iPad, etc., etc.
If your iPhone is checking your POP account then Mail.app can't log in at that time. That's a limitation of POP.
If you have a lot or large messages in your mailbox then it could take several minutes to download to your iPhone, locking the mailbox for a significant period of time.
If you truly don't have any other devices then it could be someone else is logging in as you - in which case you should check the server logs to verify.

As for solution - either lower the frequency at which the other devices check mail, or switch to using IMAP, which is more tolerant of multiple accesses.

Try downloading and testing Thunderbird to see if you like it

Dave

One of your solutions was to decrease the frequency that the devices check mail. Does this actually fix anything, or does it simply decrease the number of times the window pops up?

It won't fix anything, but it will decrease the occurrences, but not just because you're checking less often.
Let me explain… assume that when a client (either Mail.app, your iPhone, or anything else) logs into the mail server it takes, say, 10 seconds to check the mailbox for new mail and log off (longer if there's new mail to download).
Now let's say you have your iPhone and Mail.app set to check once per minute then there's a 30% chance that the mailbox will be locked when either client tries to log in (for each minute the mailbox is locked for 10 seconds by Mail.app, and 10 seconds by the iPhone).
Now if the clients were set to check every 5 minutes the lockup period drops to 20 seconds every 5 minutes, or about a 6% chance.

so it may be obvious to others, but what do you mean by "switch to using IMAP, which is more tolerant"? How do I switch? What is IMAP?

There are two common protocols for mail clients. POP (Post Office Protocol) is the original, and probably more widely used than IMAP (Internet Message Access Protocol).
The main difference is that with POP the client logs in, checks for new messages then downloads the entire message. The client also keeps track of the last message ID it has seen, so it can use that to detect new mail next time it logs in
IMAP, on the other hand, just downloads the message headers rather than the entire message, and leaves the message on the server. This makes the initial mail check much faster (less data to download) and is easier to keep multiple clients (Mail.app, iPhone, etc.) in sync.

As for how to switch, it's not easy to just switch from POP to IMAP. In Mail.app you need to create a new account (Mail -> Preferences) with IMAP.

I guess I was hoping that there might be a different e-mail program I could use?

If I'm right then another mail client isn't going to help. All you're going to do is move the problem from Mail.app to whatever other app you try.

Hey Lincoln,

Are you by chance using Google Apps to host your mail?

If you are, it's possible that you need to reset the CAPTCHA. To do so, go to https://www.google.com/a/yourdomain.com/UnlockCaptcha (make sure you switch out the "your domain" part). Enter your username (which is only what appears to the left of the "@" symbol) and your password, then click Unlock.

I am having the same problem, and now I have a new one: most of my old messages have simply disappeared. I can't remember the last time I searched for something in an email message, but it wasn't very long ago. Today when I did that I had almost no messages left to search in, and my subfolders, which I use for sorting and storage, are empty. I have been through a lot of reinstalling, new user account, and so on in the last few weeks, but this seems to be a new problem. (And I checked my account preferences; they're still the same in terms of keeping mail, so it's not that.)

I have Time Machine backups, as well as a clone from last week; is there a way I can check in there?

never mind the disappearing mail, this article fixed it: http://docs.info.apple.com/article.html?path=Mail/3.0/en/14019.html
But I still have the password problem others have mentioned.

I've had the problem for a long time. Very frustrating. Just discovered what MIGHT be a solution. I've made the changes for my account. I'm hopeful it will work.

Utilities > Keychain Access
Locate the password for the account. Example: MSN accounts are pop3.live.com and smtp.live.com.

Double click to open the window.
Select the Access Control tab.
In the box that says "Always allow access by these applications:" add Mail.

I'm not 100% this will work, but it seems to make lots of sense and feels right.

Good luck to all of us.

To add confidence to my previous suggestion:

My Mail program accesses four email accounts; I only had the problem with one of them. The Keychain Access showed that the passwords for all the other accounts allowed access by Mail - the only one that didn't was the account that kept failing.

I'm feeling very confident that this will be the solution.

My fingers are crossed.