High Mail CPU with El Capitan

Jumping in here to add my name to the list of: 222% CPU, constant 'downloading 3689 msgs' which never changes, blank msgs, etc.

Earlier this morning I was excited to see 3+K msgs actually download and everything was readable. But just now, while there are only 7 new msgs, none of them have text, and the 'downloading 1 of 6' is stuck.

Will try the above tips and tricks…

Hello,

To answer your question, the email account that causes the problem is not a gmail account. It is a professionnal email account that relies on an imap server to manage mailboxes.

Regards,

P. Degiovanni.

Ok thanks, good to know.

Hello everybody,

I'am replying to my previous email to give everyone a summary of the issue and maybe help you:

- The problem is a high CPU use by "Mail" when consulting an IMAP server. It keeps on saying "Downloading messages" and the CPU usage never goes down. In my case, the computer is a Mac Mini late 2012, running OS X 10.11.2, 8 Gb RAM and 1 Tb fusion drive.

- The problem seems to be computer dependent: at the same location, I also use a Mac Book 13" non-retina model, running 10.11.2, and consulting the same email account with the same settings and it never went crazy.

This seems to suggest that the problem may not be caused by any network configuration problem and maybe computer dependent (not sure it's a hardware problem though: maybe the mini experienced some glitch corrupting some binary file somewhere whereas the 13" mac book has not)...

- The problem occurs with one of the three email accounts configured on this computer, not with the other two although they were also relying on IMAP. If you have several email accounts configured for use in Mail, I therefore recommend that you first determine which one causes the problem. This can be done by switching each of them off (In the preference panel, by unchecking "Activate this account" box) and look when the CPU usage drops out. This will lead you to the culprit.

Everyone should perform this simple test to help localize the problem precisely.

- Following the advice by the french apple assistance hotline, I have created another user account on this computer, then logged as this user, I have manually created an email account with exactly the same settings as the one that causes the problem. Everything seemed to be fine during two days but Mail once again went crazy on the third day.

Performing this test helps Apple find out if this is a User based problem or a System based problem. Note the delay: it works fine for some time then goes mad... If you experience the problem, you could try this too.

- I tried resetting Mail configuration by quitting it, then moving the ~/Library/Mail folder somewhere else (thus, in principle, resetting user based settings), then rebooting the computer and restarting it. The problem reappears after some time with the mail account that causes it...

So far this is where I'am... So for the moment:

- I use Mail with the email accounts that do not have the problem. At least, this works.

- I have (hopefully temporarily) switched to Thunderbird for consulting my professional email account.

I'am in contact with the french assistance and also have been contacted by someone from Apple who is reading this forum. Maybe we will get some new information to help solving the problem. So stay tuned!

Regards,

P. Degiovanni.

I did as Pascal suggested:

- deactivating all accounts; (Mail>Accounts, uncheck theboxMail under each account)

- quitting the app;

- delating the Mail folder in the Library folder of my home; (hold down option to select Library in the Finder>Go menu)

- rebooting the computer with reset of the memory controller;

- on another computer that does not have the same issue, deleting …a lot of old emails

- restarting Mail

- reactivating my mail accounts

and seem to have success this morning (but as with Pascal, I'll have to wait a while to be sure.

But as of now, the emails all downloaded instantly, none are blank, all syncing correct/matching emails I read or trashed last night on iPad, CPU usage is at 4%, One question: how did you 'reset the memory controller'? http://www.macworld.com/article/2881177/how-to-reset-your-macs-nvram-pram-and-sm c.html

Also, to be safe, rename your Mail folder in the Library instead of trashing it. Then when the new Mail folder is rebuilt correctly, you can trash the renamed one.

Best of luck and happy holidays to all of us.

Hello everybody,

A quick answer to your questions:

- Resetting the memory controller uses the Cmd-Alr-P-R combination at the reboot.

- And I precisely just renamed the folder Mail inside ~/Library/ ...

As I explained in my previous email, the problem does not appear instantly after reinitializing "Mail" by renaming the folder: it usually takes 2-4 days... but once it starts, it is pretty reproducible. I'll post an update to my previous mail in order to give some extra-information.

Regards,

Pascal.

Hello everybody,

Just to let you know: we are not left alone in the dark!

Apple is contacting some users experiencing the problem to investigate more precisely what happens. I have just been given a phone call by "Bob" from Apple for this. They have run a diagnostic of the system and communicated the resulting 32 Mb of data to the software engineering...

Practical outcome of this call is two fold:

- The solution may not be at the user or even at the computer level. It may require a software update by Apple and we will know more within one or two weeks.

In the meantime, the best to do is to identify which account generates the problem (as I explained), deactivate it in Mail and, for this specific account switch to a webmail interface or an alternative software such as Thunderbird. It's annoying but at least, you will be able to use Mail for some of your email accounts, and have a temporary solution for the one generating the problem.

- It seems that many people having the problem use a Mac Mini, but not all of them.

So don't forget to communicate information on your hardware to the assistance if you contact them or even in your mail on this forum since Apple people are reading it.

Regards,

Pascal.

I have 7 email accounts I use daily for personal and business activity.
I use Outlook 2011 (but not to an Exchange server), Gmail, and 5 other POP accounts.

I work on 3 different Mac's, all current and running El Capitan without any excess CPU usage.

My suggestion is to carefully check your email ACCOUNTS, (Mail > Preferences >Accounts )

Then go to the ACCOUNTS for each email account, under the tab "Mailbox Behaviors"

I have every box checked, but you may not all those features - each takes up more work when check for new email.

Do you really need to "Store draft messages on the server", or deleted emails, or junk emails ?

Is you inbox cleaned up? That is one thing that can really improve email performance !

If email was a game, the object of the game would be to keep the inbox cleaned out.

(Having said that, I do well to keep it under 500 messages. The it gets over 1,000, I stop and clean it up).

Also, consider how often you check for new emails. If you only have 1 or 2 accounts, every 5 minutes may be fine.

But, if you have 7 accounts, like I do, push it back to every 10 or 15 minutes.

My hunch is that your Mac and your email servers haven't had time to completely sync or you are checking for new mail too frequently.

Lets us know and please share more specific details on how your accounts are setup.

I am having the same problem. Mail is pretty much unusable. I have only one account.... my iCloud account on my machine. have done the reset and cleared old emails and still the problem returns after a day. I have reset three times completely from ground zero. This started just after the latest update on the 8th. Apple, please help.

Working on a MacBook Pro (Retina, 15-inch, Early 2013), 16GB of RAM, I have similar problems.

All of my eight mail accounts are IMAP accounts.

It's mainly my largest primary account that causes this high CPU problems.

When the problem occurs I:

• delete this account from System preferences / Internet accounts
• re-create the account by adding it again

It will then re-download all the mails - and is quite busy with that, but I can work for a periode of time again.

Not the final solution though, it's only a work-around.

Hope Apple finds and fixes this problem soon.

Gerard

A very nice man from Apple called me yesterday and took some diagnosis from my machine while the problem was occurring for their tech guys. Although it's no help right now, Apple will certainly be on this and hopefully a fix will be pushed out real soon.

I could persuade my wife leaving win and join the mac world - I'm an idiot. She's annoying me each and every day with her macbook air making noise

because of hight cpu usage caused by mail.app 😠

Same problem here on macbook pro MacBook Pro (Retina, medio 2012, 2.7 GHz Intel Core i7, 16Gb RAM & 750 SSD); CPU clocking at over 200% for apple mail. Have 9 different email accounts (both IMAP, exchange and one pop).

Problem first occurred on non apple IMAP account I use. Deleted the account form mail app and then reinstalled it. Stopped the problem for that account (CPU usage back to 40%) but few days later same problem started on iCloud IMAP mail account. Same approach did not help this time... Now disabled apple mail and using Safari iCloud login to check email in icloud.

Looking forward to apple's solution for this. Thank you for looking into it apple, much appreciated!

I have had the problem off and on for 6 weeks on a 2013 Macbook air and a 2014 iMac. I leave the activity window open and visible all the time. You can see in this window when the Mail program is hung up and causing high CPU usage. I have deleted accounts and reinstated them which at times has fixed the problem for a few days. I have resorted to shutting down and restarting the Mail program. Sometime I have to do this 4 or 5 times to get all the new mail downloaded and the activity window clean. This is a real pain, hope Apple fixes this issue soon.

I have no problem on my MacBook Air with email but the problem exists for the same account on my iMac (late 2009). So it appears it could be hardware dependent rather than IMAP!