Q: Mail not working with El Capitan

Hi I updated to El Capitan a few weeks ago without any troubles as described so far.

But after the update of 27 okt Mail just did not start up without trying to check the Mail Libraries etc.

I tried several times but no results.

I use a Google account in Mail and disabled the 'connection' in System preferences > Internet accounts.

Still no results.

Then I started Mail again and got the same messages again (checking Mail Libraries etc)

After a wait of at least 4 hours Mail was ready and working again!!!

Update on my husband's Mac situation:

My husband returned to his client on Monday and he couldn't send mail AGAIN!!   But it turned out to not be his Mac's Mail that was the problem.  A switch, a piece of networking equipment that controls the flow of data through his client's computer network, was blocking port 465, the SSL SMTP port required by our ISP.  The IT guy was completely confused because it should not have been.  So we can only guess that someone did an update to the switch around the same time I had upgraded his Mac to El Capitan, which turned on (checked) those "automatically detect and maintain" options in Mail Account preferences.  So when he returned to their location and port 465 was blocked, the Mail app changed the SMTP port assignment from 465 to 587, a frequently used SMTP port.  By the way, I believe this was unrelated to continuously downloading error that erasing the files out of V3/maildata fixed.  

If your ISP tells you to use specific ports for IMAP, UNCHECK those "automatically detect and maintain boxes"!!!  The Mac Mail app should not try to change them.  If the ports for your ISP aren't working, then you need to debug the problem.  In the Mail app, select Window -> Connection Doctor and then click on tje the Show Logs button.  Scroll through the list until you find the current date's SMTP log.  You may not know what any of those messages mean, but your support person should.

I definitely feel like I have been battling a hydra, but I think for now, I have finally gotten all the heads cut off.  By the way, in all of this, I learned about TeamViewer to be able to access my husband's Mac remotely and it works WONDERFULLY!  So if you are like me and are called upon to help friends and family members with their technology, consider installing TeamViewer on their devices.  They even have apps for  handheld devices.

Looks like Apple have seen that we are all still having problems.

http://www.macrumors.com/2015/10/27/first-os-x-10-11-2-el-capitan-beta/

Hi,

After may fruitless other attempts, your suggestion to make changes through the Advanced Tab finally enabled me to send and receive emails.  Many thanks.

However, the system is constantly checking for emails as soon as I open Mail.  I have adjusted to check for emails manually only, but the checking starts automatically when Mail is opened and I cannot find any means of stopping it.  This did not happen with Yosemite.  The number apparently checked often exceeds many thousands, although there are rarely more than a dozen on my providers server!

Any further suggestions to stop this?

Whenever my IMAP mail starts acting up on a machine in the way you describe (and excess checking I have seen under previous OSes), I rebuild the mailboxes. Maybe that will help you.

If you will go look at my post in this thread from 10/25 and make sure you are seeing the same thing I was seeing on my husband'sMac, which was continuously downloading email, then you should try deleting the files in the V3/maildata folder as I documented in the 3rd paragraph of that post.  It fixed that problem.  (Sorry, the post is very long-winded.  It didn't seem that long at the time I wrote it.  I guess it was because I was struggling for days with the various problems.)

Held off El Capitan update until .1. Tonight started having the "cannot connect to server" issue with Mail and my GoDaddy aliases. As I found in this thread, I de-selected "Automatically detect.." for each alias and saved and now all is well again. For now.

Deleting all the content of the files in the V3/maildata folder, (except the content of 'rulesactivestate.plist') seems to have worked, although it's pretty nerve-racking doing it!  Can this be right you wonder.

Hugh sigh of relief though when Mail reloads and all your emails reappear.

Big thank you for the tip, which hopefully will also be useful to others.

I had an odd thing happen yesterday in that suddenly both my laptop and iMac began having a problem sending mail. Instead of mail actually sending, it would flash up again and again until I was able to drag it from the outbox to the drafts folder. That led me to go into accounts on both computers and I learned that there were additional accounts on each that had been created by cloud linkages between the two machines, essentially one creating what it found on the other. Apple engineers should look at whether this may be the culprit causing so many hassles in mail. I had linked to one email server on one machine with a pop account and used imap on the other. So that gave me in essence, two competing mail clients on each account. No wonder I was having trouble sending mail!

I had made some adjustments in accounts on my iMac following the update which seemed to have worked as long as my laptop was turned off. When I turned my laptop on days later, mail sending problems instantly arose on both machines.

What I did to get both working again was to go through accounts and mail preferences and discard the wrongfully replicated accounts and make certain that pop accounts were used on both machines and that they were perfectly in sync so as to not be wrongfully replicated in the cloud sharing between machines.

To respond to your question about being "right".  When I was researching how to fix my problem, I found old posts earlier upgrades to Mac OS causing this continuously downloading problem  in mail. Yosemite had a file that people had to delete.  I can't remember it's exact name, but  it had to do with already downloaded mail.  The next time the Mail opened, that file would re-build and the problem fixed.  Since I could not find that file with El Capitan, I kept looking for solutions and found this discussion thread.  It appears to me that now, El Capitan's mail app uses one or more of those files in the V3/maildata folder to determine if mail messages have already been downloaded and by erasing them all, we took care of the offending file(s) and the Mail app just rebuilt the files fresh.   By the way, if a person doesn't use any mail rules, he/she can erase rulesactivestate.plist without any problems.

HEY APPLE, IS ANYONE HOME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Loads of people seem to be having mail problems with El Capitan.  (When i try to send mail it goes right to my outbox and sits there)

FIX THE **** PROBLEM.

Hi the world compagny!!

What did you do since the 30th september 2015 ???

Nothing for mail !

I knew a better quality of service for this price...

unbelievable

You have experienced the problem with mixing and matching email protocols that has been around from the very beginning of email, which pre-dates the Internet being open to the public.  The various protocols (e.g., POP, IMAP) can be viewed as different languages and just like a human game of telephone in which each person speaks a sentence to the next person, imagine the person translating the sentence into a different language and then speaking it to the next person.  There is little chance that the sentence will be translated back into the original language exactly.  Well, that's what happens to an email account with devices using different protocols to manage the same email account.  As you found, you can employ different email protocols on your devices, however the protocol for a specific email account must be the same protocol on all the devices so that all the devices are managing the email accounts in the same way.

Patty, this was never a problem before as my laptop and iMac were isolated from each other. I was able to use POP on one machine and Imap on the other without difficulty. The new connection thing that is happening between computers in El Capitan has apparently made the protocols of one machine become duplicated in the other. This is new as far as I can see related to iCloud sync between related computers.

FWIW, in my case, using Mediatemple Grid, the tech support staff helped me to solve it doing this:

• deleting the account from mail (fortunately, I was using IMAP, so I didn't lose any mail)
• resetting the pass (using MT control panel)
• re adding the account
• they un-banned my ip because it was banned for the multiple logins attempts

So you could try these steps and asking for their help if you are in MediaTemple