Q: Mail not working with El Capitan

I have Road Runner e-mail and was having the same issue. Road Runner helped me to correct the problem by setting up my e-mail again thru an imap server instead of pop server which I had before. Hope this helps some people.

Having just upgraded my old MB Air (late 2011), I was disappointed to find that mail kept failing  As soon as I tried to start the program it fell over so I could not get into it to change the account attributes.  Eventually found a fix inspired by these posts.  Preferences>Internet Accounts and unchecked Mail in the  Gmail Imap account.  This enabled the apple mail program to launch.  With this running I then went to Mail>Accounts and deleted the Gmail account, closed the program, relaunched it and then re-established the Gmail account and all is working fine.  Hope it helps!

We have a similar issue.  At our University we have several hundred Mac computers of various types.  We use Google Apps for Education with a Single Sign-On server for our email.  We had to notify our users to stop upgrading to El Capitan.  Once they upgraded, the user could no longer access their Google email accounts.  Most of our users have setup accounts in Apple Mail using the Google account option.  There are very few POP/IMAP setups on our Mac computers.

I have been working with Apple for three weeks now.  What has happened, in our case, is Apple Mail is not allowing the authentication to our SSO server anymore.  I have erased, formatted, and installed El Capitan again... this did not help.  El Capitan introduced a new layer of protection for the OS against malware and spyware, which can only be disabled/enabled in recovery mode.  We disabled this feature.  We checked the keychains and SSO certificates.  Nothing we did helped.  the account setup just sits waiting for a SSO login that is not being displayed.

I finally erased, formatted, and reinstalled Yosemite.  Everything works again.  When I setup a Google account I see the SSO login prompt again.  Of course, this action is a bit extreme and, for the most part, our users will not be able to do this

I'm waiting for Apple to call back today.  In the meantime, we are stuck in limbo.

22 pages of comments should be "proof enough" that something with Mail is seriously amiss. I have similar problems - Mail crashing, clicking on a specific message comes up with the wrong message, spinning disks of death, buttons (like "allow access to keychain") in pop-up windows simply not doing anything (and no way to dismiss the pop-up window) - it's not just one problem. Add to that the erratic behavior of the El Crapitan interface in general - dragging something onto a folder may or may not (randomly) highlight this folder, so when I let go of the mouse button, I can only GUESS whether the transfer will go off as planned. I also saw examples of VGA projectors crashing a presentation, etc. etc. - all due to an upgrade that was touted as IMPROVING stability. (Ha ha!)

I agree with many of the other voices on this forum - Apple dropped the ball and upgrading was a big mistake for me.

I tried that but I still can't use mail, it keeps asking for password, I enter it says it is wrong I change it reenter it says it is wrong so fustrated

Once again I come back here to complain about the worst Apple email application ever. This application, besides all the hundreds of problems indicated by my colleagues I am dealing not with two more issues; first permanent disconnection to the mail servers, causing you to have the try to re-connect every minute, no matter if you have SSL or not selected. If you do no have selected SSL, ports 143 and 587 for incoming at outgoing mail server respectively, and you have saved that option, the application without your permission just come back to SSL connection. Do not matter if you have select to allow insecure connection, always It is crazy this mail behavior. Second the mail application creates several boxes for Sent messages, one is only Sent, and second one is Sent Messages. The application one time puts the sent message in one the next in the other, without any criteria, this means most of time to losing your sent messages, causing you serious problems. Not only that but worst, if you have more than one computer, those two mail boxes never are synchronized, meaning that one message sent in your desktop, most of the time never will appear on your portable.This is the most chaotic application ever. Surprised me that Apple has not solved any of the hundreds of issues that all of us have consigned in these forums. There is not one single friend or colleague with Mac that is not suffering this awful situation. I have learnt that many universities, and businesses with Apple computers have complained Apple, trying to get solutions, but none of us have have heard a single word from Apple andor  its support people. What a mess...How much we will have to wait to have promptly an Apple solution?

Had the same problem, never resolved it in my original user account on my iMac. My wife's account works fine. She has a different apple id

Finally just created a new account on the iMac, all works fine there. Slowly migrate everything into that new account, registrations, keys, serial numbers.
Tedious but it works.

Right now still switching between the two accounts. Mac mail, calendars works only in the new account but at least it works and no mail security issues by clicking off the so often mentioned authentication button.

Just for the sake of completeness, here are a few MORE "features" (bugs) of Mail in "El Capitan":

- Super-finicky reaction to mouse movements - if I hover over a message in the list, it immediately swings left to reveal a "delete" or other option.

- Messed up coordination between the message list and the actual message shown - occasionally, if I highlight a message in the list, the one I see is the one before or after in the list

- constant "busy-bodying": Even the slightest action leads to Mail doing something immediately, which it proudly announces at the bottom of the folder list, thereby moving everything up and down constantly - trying to click on something becomes a game of "whack-a-mole".

- In general, mail is so busy doing things behind the scenes all the time (even AFTER I set it to only get new messages every minute, instead of instantly), that it often freezes. I've had to quit mail and reopen it (or, worse, kill it) too many times to count, because it wasn't reacting to anything I tried to do, and instead kept working on something arcane in the background.

- More generally, because of all kinds of instabilities, "freezes" and erratic behavior, I find myself restarting my Mac at least once a day - while under earlier OSs it ran smoothly for WEEKS without restart!

Just for clarity: I have a pretty powerful Mac (MacBook Pro Mid-2014, 2.5 GHz Intel Core i7) with plenty of memory (16GB) and "disk" space (over 150 GB). And none of these problems before upgrading to El Crapitan.

P.S.: I read recently that Tim Cook was boasting about the new iPad Pro: "Who still needs a laptop?" If that's Apple's attitude to power users that actually need serious work done (instead of a pretty shiny toy), we are all doomed. Time to look at LINUX again...

I had the exact issue where tons of emails are re-downloaded over and over again from an IMAP server. Changing the preferences (ssl, automatic updates,..) did not change anything, neither did the wiping out my Mail folder and plist.

In the end I had to go through the logs to find the exact mailbox which was the culprit. Detailed explanations in this post.

So tonight I have downloaded the long awaited El Capitan patch, which I hoped would permit me to re-create my mailbox, that I was advised by Apple Support to delete way back on October 7th.

But the issue I have encountered since first installing El Capitan remains.

I am unable to estalish the mailbox on my iMac as a POP despite entering the correct information. I still get the 'Unable To Verify...' error message.

Thankfully, I am still able to receive these messages via my iPhone and iPad.

So no change for me.

Here's hoping for better news from the many others who have found it necessary to vent their anger and disgust at the shoddy and ill-thought out El Capitan on these forums.

What is certain is that a number of people I know within professional environments have decided against using Apple based OS systems again, as they have been embarrased beyond belief in the eyes of their customers and clients by the less than reliable mail offering.

Wow, so many people with the same problem.  I originally wrote out of desperation after hours with Apple support still did not fix my problem.  With a five day wait to go to my local Apple store for support I went back and did what Apple support  did and it worked.  I don't know why it took doing the process 4 times before it worked but it did work.   I deleted my account from my computer and reinstalled it.  It works now!  Might be worth a try before creating all new accounts!  What a pain!

Looks like the fix is in 10.11.2 is out and I dear to say, my old user account on my mac is working again. iCloud, mail, user accounts, calendars, iTunes all working in tandem.

I can quit working out of two accounts. Works for me.

Cheers

Latest update didn't do anything for me. My Exchange account still crashes Mail.app.

God, I hate Outlook . . .