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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

Jan 6, 2016 4:55 PM in response to BriPhil

BriPhil says:


While OS X is inherently much more secure than the-operating-system-that-shall-not-be-named, the only truly invulnerable computer is one that is BOTH air-gapped (not connected to anything else) AND completely shut down. Viruses that target the Mac platform are relatively rare at the moment, and they're generally not able to do as much damage for now, but both of those circumstances are beginning to change as Apple's market share continues to increase.


If you're very disciplined in your browsing and e-mail habits, your Mac can (probably) survive a bit longer without protection


... and i wholeheartedly agree with both. Sadly, the first is correct, we have been safe only because we have not been worth targeting. now we are.


Happily, the second remains true too. Avoid dubious sites, never say "ok" to anything, set OS X to ask for permission before instilling anything, don't follow suspect email links, and you will be safe 99.something % of the time.


I have yet to see active security software that was not trouble - on either platform. A check, like Malware bytes, that you run, is typically innocuous.


And i just updated my 3rd machine to X.11.2 with no issues, and am typing this on it. As to mail, i have a gaggle of IMAP accounts.


Grant


ps: strangely, firefox only showed the first 4 pages of this thread. Safari shows them all.

Jan 8, 2016 12:55 AM in response to andaro

Hello everybody,


I have also experienced the high CPU Mail problem and posted on this forum.


Three days ago, I have deactivated Avast email agent and reactivated the IMAP account that was causing the problem with Mail. So far, the problem has not reappeared which is a good sign since it usually starts within two or three days.


It seems that several mails on this forum point towards a correlation between the email agent in Avast and the high CPU mail problem!


Regards,


P. Degiovanni.

Jan 8, 2016 1:15 AM in response to Pascal Degiovanni

Hello again,


To complete my previous email, there seems to be issue concerning Avast email agent and secured ssl connections which are used to communicate with IMAP servers:


https://forum.avast.com/index.php?topic=129505.0


I'll try to investigate that more precisely but not before the week end... What I will do first is confirming the correlation between Avast email agent and the Mail high CPU problem by restarting Avast's email agent and see if Mail goes mad again. Then only after this, I'll have a closer look at Avast...


Regards,


P. Degiovanni.

Jan 8, 2016 5:17 AM in response to GerardFromUlrum

Folks, i know that these are annoying, but you need to look for the incompatibility, not yell for Apple (which rarely, if ever, participates here anyway).


As i have noted, i have mail, with myriad IMAP accounts, working on several systems, all El Capitan, and as old as mid 2009. They work great (in fact X.11.2 make sit faster). So do a dozen people i know. This proves that if installed correctly and without 3rd party issues, it works.


Note that AVAST, which many seem to like, shows just how either clueless or insensitive software firms can be. I went to their site and despite looking found nothing about El Cap incompatibility - yet we KNOW IT IS NOT. So dont assume that your software works with X.11.2. Check it all first.


Clearly AVAST is one culprit. There are others. There can also be errors on upgrade/install which are really annoying, hard to find and fix (might require a clear install).


This is why most knowledgeable people advise a full, bootable clone before nay major upgrade.


Hope is not a strategy.


Grant

Jan 8, 2016 5:43 AM in response to Grant Lenahan

Grant -

WIth all do respect this is an apple and apple mail issue. Not a "I F'd it up" issue

  1. I Have nothing on my computer that was not downloaded from the apple store
  2. I Only have 2 accounts in mail - an iCloud, and a work Exchange account.
  3. My problem was only fixed when I deleted my iCloud account (yes Exchange actually worked quite well)
  4. I put my @me account and ran with Unibox for two days without issue
  5. The minute I put my iCloud account back into apple mail the high CPU issue started happening agaiN causing my fans to go into overdrive.
  6. I am now going drive 1 hour from my residence to go to an Apple Store to have my issue trouble shooted because apple can not assist over chat or phone.
  7. I have every right to be frustrated at apple and their crappy mail app

Jan 8, 2016 5:50 AM in response to brown607

I didnt say you did it. I said that:


"There can also be errors on upgrade/install which are really annoying, hard to find and fix"


But that's not the same as a coding error - i trust you see the difference.


I will accept your statement but find it hard to believe that all your software is from the app store. No office? Firefox? Nothing?


Good luck. But answer this - why do millions work and 100s, maybe 1000s don't? Computer code is very objective - it works or doesnt.


Honestly good luck, btu look in the right places.

High Mail CPU with El Capitan

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