Q: Mail not working with El Capitan

So after wasting a ton of time rebuilding mailboxes, the problem persists randomly every day or two with exclamation marks all over the folders in mail, telling me there is a problem with the server.  Um no, there is not - I run my own server with multiple other users, I realtime watch the server logfile and see other people and also webmail logging in and out no problems.  Upon closing and restarting mail or running connection doctor IT DOESN'T EVEN TRY TO CONNECT.  This made me suspect a wifi issue since that's been randomly hanging as well.

So the past couple times it's happened here I've 1) Quit Mail 2) Turned wifi off, then back on 3) Re-opened mail and it magically connected.  So hopefully for some others out there this "fix" will help before you go off wasting hours and hours of your life rebuilding mailboxes when maybe you did't have to. 

Gotta say, this is a brand new Macbook 12" which shipped this way out of the box and paid nearly 2 grand for - it is TOTALLY RIDICULOUS that we are having issues like this in 2015 - particularly after paying this much money.  I really wish companies would stop trying to turn PAYING CUSTOMERS into their QA departments (not just Apple - it seems all of them these days). 

Mail in El Capitan finally swallowed the message that caused it to hang and is now working!  After days of starting and restarting the transfer process and watching it hang for hours each time, I finally let the transfer work overnight.  Given about a day to chew on the problem message(s), Mail completed the transfer and now works flawlessly. 

I can't believe that it's taken a month and nothing has been done about the mail issues and the apple id problems. We use two apple accounts and my partners account is working fine. Mine is a total disaster. All mail accounts gone, apple id, password rejected.

I wonder if the problem has to do with the two accounts on my iMac. On my laptop it's just me and everything is fine with 'El Capitan'

My documents folder shortcut disappeared form the left panel and mails are not being sent from Apple mail after I downloaded El Captain. the out going mail settings disappeared and inspite of deleting the settings and adding them again , it's still not working

Until El Capitan is really fixed (they are doing a beta test of a new version now), I decided, after many hours of trying to fix this, to Restore the last OS version from Time Machine.  It completely fixed my issues, taking me back to the safety of what I knew worked. 

Same thing here....

Exactly the same problem. I have my own domain name with e-mails which were working perfectly this morning. I upgraded to El Capitan and Mail received OK but would not send. I deleted the e-mail accounts and re-installed them and it made no difference. I then called Apple Support (who didn't charge me) and even they couldn't fix the problem, despite being more than eager to help. They managed to get one account to send and receive but it wouldn't send to multiple recipients (erratically - sometimes it would send to up to 5 but on other occasions it would only send to one).

I didn't buy a Mac for this sort of rubbish so I've restored Yosamite and will be sticking with it until I am satisfied Apple have sorted it out. Until then I'd avoid El Capitan like the plague!

Mail keeps claiming more memory and more swap space, clogs disk and memory transfer. Also it claimes more than half of the total CPU power on my iMac.

When I first detected this, mail used 60 GB of memory. Rebuilding mailboxes did not help. I can only switch off mail and only switch it on when reading mail.

How can such an important functionality be rolled out without any testing ?

I should be paid by Apple as a beta, wait, ALPHA tester.

First "no wireless" Yosemite and now El "no email" Capitan.

Apple, do less marketing and focus on programming. You are going downhill.

Why should I not change to Windows? It is also bad, but cheaper.

I too am having problems with Mail having upgraded to El Capitan. Despite two attempts by Apple Support to resolve (I have to record they were very helpful and sympathetic - full marks for that!) I still find that when I log off my password for the outgoing server is wiped. I then have to resubmit the next time I open my machine and it takes an age for any emails to be sent whilst the outgoing server reestablishes contact.

Given the variety of different symptoms recorded on this thread it does seem to point to a deeply defective upgrade. Surely it should have been resolved by now?

I am still awaiting a solution to my mail problem, which has inconvenienced me since upgrading to El Capitan on October 8th.

The promised hope of this being resolved with the release of the patch proved fruitless.

What is interesting to see is how Apple Care/Support have now shifted their default arrogance from 'not our problem' to acknowledge their inability to remedy the issues caused by El Capitan.

When I enlisted paid for 'Care', my issue was dismissed without resolution and the blame being placed at my POP email service providers. Apple were not interested in hearing that the email servers were working normally as I was able to receive mail on all other devices not running El Capitan.

I did as I was told and deleted the mailbox altogether and reinstall it but since them I have been unable to create the mailbox again and even get the server to recognise the password. The 'Cannot verify account or password' message is all I get and despite making use of the various approaches given in these forums,

I am still without access to that professional mail and the loss of all previously held mail.

I am not technically savvy and did not want to start messing about with Library V3 files.

I am sorry to say and to my shame, I took comfort from knowing that the issue I was experiencing was widespread and was/is being caused by El Capitan.

However, one month after the release of the problematical El Capitan with one further patch, I and many others still await resolution.

I just switched to Thunderbird. I actually like it more because with 1 click I can sort on date or sender, like in osx mail in better times.

Setup is easy. Even if mail is fixed I will stay there.

Mail is just a GUI and a database manager on top of the eternal unix program mailx.

If Apple can't maintain GUI's and databases, what do I need Apple for ? Nothing.

Note that I have used Apple since 25 years and never liked windows.

Apple, it's got to be perfect or you will lose business.

SO, today I get a notice that there is an update to El Capitan. Naively optimistic that it will fix the problem that prevents me from sending apple Mail. NOTHING!!!!!!!!!!!! Can anyone tell me how to revert to Yosemite.?

thanks,

BIll

If you have a time machine backup it's fairly easy. Restart your computer and hold Command  and 'R' at the same time. You than will be prompted to either install OS X or install with your time machine. The OS X install will be El Capitan again.

On your time machine find the latest backup you have with Yosemite select and install. For me everything was back to normal.

If Apple Mail is not connecting with your Gmail account after a new installation of El Capitan, it is because Google has declared Apple Mail to be a "less secure" program. you have to log in to Gmail online, see the email you probably just got entitled "Sign in attempt prevented", click on the "Learn more" link in the email, then choose the option to give "less secure" apps access to your account. If you didn't get the email, you can probably find this in your security settings. Voila, Apple Mail works with your Gmail account again.

Way to go Roderick; your the man Thanks Tom