Q: Mail not working with El Capitan

El Capitan does not work with Mac Mail. I upgraded my iMac but not my MacBook Air and other Mac computers. Now my iMac does not work on Mac Mail. My other computers are fine. This is the first time a Mac upgrade was such a disaster for such a core program as Mail. My whole business depends on reliable mail, and now my entire support system has been upset. Downgrading is very time-consuming and an embarrassment to Apple. This is something I would expect of Windows, not Mac!

Go back and read other posts with solutions that have worked. Particularly the ones that suggest unchecking automatically detect and  maintain account settings under Advance under account settings.

Useless, non of the suggested ways to solve the problem worked in my case. I tried for hours.

I already read most of the posts over the last month. The clear consensus is that Mail is a disaster with El Capitan. I've tried most of the fixes suggested and they are at best temporary. I  unchecked the auto detect box days ago. I just looked and somehow it was re-checked. I unchecked it again and will see if that helps.

I would suggest not wasting your time with things like deselecting and reselecting 'Auto detect settings', after my update and trying to fix it by trying to reset the settings in Mail that the upgrade to El Capitan wrecked for me, I had to contact my server 3 times to get my IP address unblocked because Mail was pinging the server so much with wrong settings that the server locked my computer out!

Solution: Revert back to your last saved copy of Yosemite, it will save you a lot of time over mucking about with what is a poorly produced software application.

I agree. I just want to keep making noise about this problem. It has been a month and still no solution. I went back to Yosemite once already and I don't want to do it again because of other software package issues.

Making a noise here does not have any effect with Apple unfortunately. My cut on Apple is they are more interested in their mobile devices and iPad OS side as that is where they make most money, maybe just a coincidence that many of their apps I n the last 2 OS's have been a mess, the standard of OS such as what Snow Leopard was at is probably a thing of the past with Apple sadly.

Agreed. I hate to keep at it for the same problem. I've found downgrading to Yosemite fixed a lot of the issues, not just the mac Mail problems I've been having. I remember reading somewhere (I forgot the actual source) that iOS 9 was only in Beta 1/3 the time of other iOS releases. I suspect El Crapitan might be a similar story. Anyways, Yosemite works fine for now; give it a few months and maybe Apple will resolve some of the issues. So far, I have yet to hear anything resembling Apple's recognition of the 10.11 problems and plan to implement a fix.

Since my wife's account worked perfect, I created a new user account on my iMac and it all worked fine there. In the process of getting rid of my old user account on my iMac. My original user account will still not accept iCloud in preferences and my iCloud account is grayed out and inactive.

May one way to go?

I have read literally every posting regarding Apple Mail issues under el capitan. I have tried everything - checking & unchecking automatically download, testing in test user, blowing away el capital and reinstalling, blowing away the entire startup drive and starting from scratch. nothing works. have spent hours with apple mail specialist - lovely, patient person, sending data reports to apple engineers for analysis. No joy, ever. office 365 (the problem account is an Exchange account) has no idea except to dig up forum posts, which - believe me - i have read and tried every suggestion. now use Outlook for Mac, which as a business tool is very limited - no smart filters, no plug-ins like MailTags or MailHub to make using in a business environment workable. very, very bummed, especially as a 30-year mac user and evangelist.

I've had the same exact issues. I can't say I've had this much of a problem with an upgrade - ever - with an Apple product. Even if I could get Mail to work in El Capitan, it would work only for a short while. It's been several days of useless, wasted time on this, so I've migrated my key accounts over to gmail where it's possible to send out mail using my own domains. Even this, however, is not ideal.

On the upside, there's a much better, faster system for weeding out spam in gmail, whereas Mail "rules" are tedious to set up. Why can't Mail simply allow the click of a "block" button to dispatch the evil spam?  Oh Apple!

How did I get here? Oh yea, like you I upgraded to El Capitan. It made sense, because I recently started using Office 365. An I shared your sense of outrage when ~both~ my domain mail accounts were affected. I could receive mail, but I couldn't send replies. I spent several hours working through this with my domain's tech support. Here's what I learned in the process:

El Capitan automatically changes mail account settings to IMAP server. This is good because many cloud applications (iCloud) talk with each other and sync. It's bad because many email accounts (including one of mine), use POP server protocols.

If this is true for you, go to Mail Settings, create a 'new' mail account using "Account Type - POP" (not IMAP) server.

First, you'll be prompted to input your name, email address, and password from your previous settings. These may be saved in Keychain, or elsewhere. I try to save using both so I have a reference place outside of Keychain. Then choose 'Next'

You'll see another pane with fields for email address, user name and password. Populate those with your previous settings.

For the "Account Type" select POP

Populate your Incoming Mail Server and Outgoing Mail Server with your previous settings.

Sign in.

Success! (or, call your domain's Technical Support line).

For IMAP:

My other email domain is IMAP, because I use it through iCloud to sync mail, calendars, and now even my wireless calls and FaceTime. Since El Capitan told Mail Settings to make this an IMAP account it shouldn't have been a problem. Right? Not so much.

It seems the bug in this soup is SSL. My tech support suggested this workaround:

Under Settings, go to the Advanced tab and deselect "Use SSL"

Or, just reset the account to POP settings, which is my temporary solution for the mail account I use most.

This bug isn't completely resolved for me, but the workarounds got me back in business. I hope this helps.

My issue is kind the reverse. I have gmail account (which I believe is IMAP) and it works fine with El Capitan. I also have a Rogers account (operated by Yahoo) - which is POP. The POP account periodically looses or forgets the password authentication, so each time I have to go in to the account, change the authentication method from none to password, then my e-mail address is automatically populated and I enter the password. After a few seconds, the account is re-connected and I'm good for about 24 hours.
I've tried adding the account again but it won't let me proceed, as it recognizes that the e-mail address already exists.

I can't uncheck the box "automatically detect and maintain account settings" as it's checked and greyed out, not allowing any changes.
I have not contacted Apple as that seems to be a waste of time and effort judging by other posts.

It's too bad a lot of people are opting to disable SSL, and that it seems to be a problem for lots of folks.  SSL has been around forever, and particularly in today's world SSL should be considered very important to the point of necessary.  Otherwise your login credentials and all network traffic including your emails that come and go, are trivially sniffed over the network.

It sounds like a lot of the troubles are with huge email providers as well, where it's almost impossible to get anyone on the phone who can help.  For those who can, maybe it would be helpful to look into much smaller email providers who will charge a small annual fee but you can actually get hold of someone who knows what they are doing.  I do NOT mean some kiddie who installed cPanel on some little box somewhere, but rather a small hosting company run by someone who is an experienced, professional administrator who understands how to hand-configure their mailserver and scrutinize/parse logfiles - and has actual administrative access to login to your mailserver.  So that you can get some real support, not someone in a callcenter sweatshop going through a bullet list of questions with you.  

Although I had it crapitan out on me after "fixed" a couple times (would work for a few days to a week and happen again), it's been about a month now and I seem to have found the magic combination for my case.  SSL is enabled for mine (anything else is unacceptable - I will switch clients otherwise), everything is IMAP, and "Automatically detect and maintain account settings" is UNCHECKED.  Whoever cooked up that checkbox should be fired; simple email client configuration is not rocket science - email has been around for over two decades now and you only have to do it once in a blue moon. 

I really don't think email providers have anything to do with the problems that are happening here zeugmatis, I think these are Apples problems... caused 100% all by them and their developers! In my case and from what I can read, these email accounts that the El Capitan upgrade messed up all worked for people before the upgrade so I really don't know where you are coming from on that one!

Moving on...

I had most of Sunday available to put my feet up this weekend and decided to have a look at a second attempt at upgrading to El Capitan, now knowing how easy it was to wind my computer back and after thinking about the problems, so this is what I did to get my laptop and Mail app to work with El Capitan, just a word of warning though, it was a bit of a laborious process considering I have 12 email accounts but hopefully most people don't have as many and so a little less time consuming but of course if all goes well then it is fully worth putting in the effort, so this is what I did to get things to work:

1) Opened Disc Utilities and selected to Fix permissions

2) Went to Mail app and opened Internet accounts (I had to select to delete an email account to get this option then not actually delete the account when Internet accounts opened)

3) I deleted every Notes account for each email that the OS had created without my knowing, I don't use them.

4) Close the Internet accounts window.

5) I opened each email account and took screen shots of: Account information tab window, Advanced tab window. So I had a copy of all the settings that actually worked on my email accounts.

6) Opened the SMTP server window and took screen shots of the Accounts information tab window and Advanced tab window.

7) Moved all the screenshots into a folder on the desktop.

8) Made a complete backup on Time machine, took about 10 minutes or less.

9) Closed every application that was running and restarted the mac.

10) I had ran the upgrade to El Capitan before and wound back to Yosemite after the issues I had a few days ago so I still had the Installer 'Install El Capitan' in the Application folder it was download to, I double clicked it to run it.

11) I followed the prompts I entered my password and ID for iCloud as asked by the installer, I noticed this time it asked if I wanted to confirm File vault setting to encrypt, I deselected the checkboxes for file vault option as I did not want to encrypt my files, at least not for the moment. I do not remember the installer asking me this option the last time I tried to update to El Capitan... I wonder if it just tripped over that and encrypting things was the problem, anyway.....

12) After the computer restarted and was ready to try and open apps I disconnected for the internet so Mail didn't connect to my server for emails, I did that because my server manager said it was bombarded with connection attempts by Mail the last time with wrong passwords and port information causing the server to block my IP address... 3 times in about 20 minutes.

13) I opened Mail app and deactivated all my mail account accept one.

14) I checked the settings for that account 'especially port numbers, if the POP and IMAP accounts where still POP and IMAP accounts' corrected information that was missing or not matching the screenshots for that account then closed the account window and saved on any prompt, not forgetting SSL settings of course along with making sure you enter the correct passwords for the account.

15) I opened Mail preferences and then selected the same account then checked that the information for that account had actually been saved.

16) I closed the account window and connected to computer to the internet and tested that one account for sending and receiving.

17) When that account worked I then did the same for each of the email accounts one at a time.

After the above process I have found no issues with El Capitan 'As yet', I worked with it for a couple of hours in the evening, an hour this morning and another hour this afternoon and so far so good with email accounts seemingly keeping the stored information and working.

I hope this is useful for anyone attempting the upgrade or feeling up to trying a second attempt, good luck.