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High Mail CPU with El Capitan

Since upgrading to El Capitan, I noticed the Mail application using a lot of CPU. About 80-90% sometimes.

Then going down to a few percent and then without any reason going up again.

Did a few times a "Rebuilt Mailboxes", but that did not help.


Any suggestions to repair this?

iMac, OS X El Capitan (10.11), 3.06 Ghz, 8 GB

Posted on Oct 10, 2015 10:33 PM

Reply
198 replies

Jun 13, 2017 11:33 PM in response to dbouws

Hi all,


I've had recurrent high CPU usage issues with Mail for Mac for a couple of years now, since upgrading first to Mavericks, then to El Capitan. Having roamed support forums for months, I tried every possible fix suggested with no effect at all, and finally decided to switch to another e-mail client. I tried Airmail for a while, but it was not convenient enough to manage the dozen or so accounts I need for business purposes. And finally, last week, I found the dreamlike solution: Postbox 5! Its costs about 40 €, but it has all the functionalities of Mail for Mac, plus a few valuable extra ones, a nice GUI, and wonderful support. No more CPU/memory/power overload, no more rainbow wheel, no more forced re-start! Apple, your Mail app has become a liability - either fix it or dump it ...


My advice thus: stop wasting time fixing Mail for Mac, go directly for either Airmail or Postbox - whichever is more suitable for your email handling habits. And no, I'm not paid by either of them - I'm just a Mac aficionado tired of being confronted with a serious problem with what is supposed to be a seamless Apple application ;-)

Jun 14, 2017 4:21 PM in response to Raffy1

@Raffy1, I couldn't agree more with your request to Apple to dump Mac Mail ... or fix it. My Mac Mail became unmanageable for that same reason, and switched to Mailmate. Though not ideal, I'm overall pretty happy with it. Biggest problem still is that Mailmate is a one person product, and hence what if the person stops... Few things I'm not extremely happy about is the html side, such as making HTML signatures (without having to write code...).

Oct 21, 2015 11:18 PM in response to Raffy1

What helped me a bit with my IMAP mailboxes was to delete the accounts and re-instate them. That's - I think - a level deeper then rebuilding. It now went down to about 15% CPU. Still ridiculously high.


Then I realized I have two accounts that work with Exchange.

  • one with pod15nnnn.outlok.com central server, when I changed that to "Use offline" CPU dropped with 5%
  • another with a company local server, when I changed that to "Use offline" CPU dropped with 10%


So the two M$ accounts where responsible for at least part of the problem.


For the rest: I hope Cupertino finds a solution for this.

Oct 22, 2015 10:27 AM in response to Raffy1

Still the same in 10.11.11!

AThis morning, after rebuilding the mailboxes, bij the installer, Mail is downloading all mail again in a rediculous slow pace.

I's been downloading mail (I don't know from where) all day now (done 2000 in 8 hrs time and 30000 more to go.

CPU use between 60 - 90% all the time.

Dec 10, 2015 10:36 AM in response to Raffy1

It's weird...one has to wonder if Apple uses...lead-alone....tests there products these days. The latest version of Apple Mail...like everyone else here is causing a major CPU hit and heating my machine causing major fan usage.


I've also experienced that colour flags have been screwed up and I have lost a ton of flagged emails or where the colour of the flagged emails have been changed from orange to red. What a waste of my ******* time.

At 47, my next machine may have to be on the Windows platform for the first time in my life.


Dear Apple...what's going on?

Dec 14, 2015 2:17 PM in response to Raffy1

Hello,


Same problem: the mail application is a total disaster on El Capitan. It suddenly start to eat all the CPU.


I have already spent 2 houys discussing with an apple hotline... They suggested switching off the accounts, then quitting mail, resetting the memory controller (requires rebooting), deleting the Mail folder in the "Library" folder, then restarting the Mail application and switching the accounts "on". This time-consuming complete reninitalization ony cured the problem for a few days but it came back. Most annoying is the fact that no diagnostic is available!

The El Capitan "Mail" application clearly has a serious (and probably basic flaw) which requires urgent fixing from Apple engineers!

In the mean time, I'am afraid that avoid purchasing any new Apple computer may be the only way to save your time and money...

Regards,

P.

Dec 16, 2015 12:56 AM in response to Pascal Degiovanni

Hi everybody,


Latest news: I opted out for a full reset of the Mail program:


- deactivating all accounts;

- quitting the app;

- delating the Mail folder in the Library folder of my home;

- rebooting the computer with reset of the memory controller;

- on another computer that does not have the same issue, deleting 90% of my mails in incoming mailboxes so that there are now less than 100 total in three mailboxes;

- restarting Mail on my Mac Mini

- reactivating my mail accounts


First, all was fine. Then I quitted Mail, switched the Mini on sleeping mode and went to bed.


Now when I relaunched Mail on the Mini, again full CPU!!! The "Activity window" says that it's recovering email...


I suspect that the problem is related to IMAP: I have also archive mailboxes on the IMAP server (useful to keep important email on current affairs available from various computers). At the same time the connections are very active, whereas they should not. It keeps repeating:


READ Dec 16 09:53:38.216 [kCFStreamSocketSecurityLevelTLSv1_0] -- host:imap.orange.fr -- port:993 -- socket:0x7fe8a150ac50 -- thread:0x7fe8a1611610

* 188 EXISTS

* 0 RECENT

131.24 OK Completed


WROTE Dec 16 09:53:38.226 [kCFStreamSocketSecurityLevelTLSv1_0] -- host:imap.orange.fr -- port:993 -- socket:0x7fe8a150ac50 -- thread:0x7fe8a1611610

132.24 EXPUNGE


However, switching off the orange.imap.fr account did not cure the problem! Another account is responsible for the high CPU problem... Hope it helps!


Regards,


P.

Dec 16, 2015 2:22 AM in response to Pascal Degiovanni

I'm having the same problem. Is yours a Gmail account?


I noticed mine started when I opted for Gmail's larger storage option, I'd exceeded the 'free' banding. As soon as I've done that I've had all these problems, mail never finishing downloading (my mail account is constantly on 'downloading messages', high CPU usage for Mail and fans on overdrive, mail arriving really slowly etc. I've reverted to using the Gmail web interface.


I've cancelled the additional storage and deleted a lot of my older emails so I can revert to a free account to see if that returns Mail to 'normal'. Unfortunately, I have to wait until Dec 24th for my Plan to revert back. If it works, this could be the best present I get this year!


I should just add, I have two Gmail accounts, one of which is working fine, it's the larger one that's creating an issue. If I turn it off, Mail seems to work fine with the other one and my Apple account. I've also tried all the options of rebuilding, re-indexing, removing the account completely, etc.

High Mail CPU with El Capitan

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