High Mail CPU with El Capitan

Would have hoped! Installed it, but my mail still syncing at 200%CPU with same problems as before... so currently stick to MailMate despite the few weaker points on HTML formatting... 😕

I can confirm that the problem is still there in 10.11.3...

Yep! All along I was blaming my high CPU mail usage (upwards of 200% and CPU temps at 70 C with nothing else going on) on El Cap but realized this morning the problem also coincided with installing Avast; I simply turned off the 'mail shield' and, so far, my mac is behaving normally again.

If the problem resurfaces, I will re-post.

Wow, my Mail app is down to 0% (when I'm not using it) after disabling Mail Shield. Thank you soo much, Joe!

After months of trying EVERYTHING I could and chasing up every post I could find, this was the one that healed the issue. I never thought Avast would cause such issues. Thanks for that!!

Unfortunately the new El Capitan version has not fixed this issue for me. I'm still getting a freeze for a few seconds when accountsd is at maximum CPU, followed by very slow response for a few seconds when Mail is (presumably) fetching new mail from the Google IMAP servers. Presumably the hit on accountsd is triggered by Mail saying "time to fetch the mail" and then doing some kind of check for which accounts I've got, then once that's complete Mail itself synchronises mail in the local IMAP folders with those on the remote end.

I don't have Avast or any other mail checker, but I do have several different Google-based IMAP accounts and one POP account.

Hello everybody,

Reading the many mails of this thread, it seems that there is a pattern emerging:

1. Avast seems the be at the origin of the problem for many users (not everyone but a significant part). So let me recapitulate:

- deinstalling Avast seems to work but is leaves you with no anti-virus or you have to install another one;

- deactivating the mail shield in Avast works but you're left with a partial protection;

- for me, on my Mini, I have reactivated the Avast mail shield but without the IPv6 option (since I don't use it). This has worked for a week now except one day after I activated the Wifi to transfer photos from my iPhone onto the computer using Airdrop.

The point is that this computer is connected by an RJ45 cable! So I suspect that Avast got lost once again when the Wifi was switched on. Deactivating the Mail account that led to runaway, switching off the Mail shied, then deactivating the Wifi, rebooting and then restarting Avast Mail and reactivating the IMAP account in Mail brought me back to a normal CPU use for Mail.

Another hypotheses which I haven't tested is that there is also an issue for Wifi users. I'am not sure that this is the issue because I experienced the high CPU problem even without Wifi but well, strictly speaking I haven't tried to use only Wifi to connect this computer.

Conclusion: there is probably something a problem related to network in the weird behavior of Avast & Mail when mail shield is activated. Be careful not to have two network interfaces (Wifi & Ethernet) activated at the same time. It's just a guess but maybe worth checking ...

2. El Capitan 10.3.3 does not seem to fix the problem according to several Mails. It does not seem to make it worse though :-) ...

3. Mail usage varies depending on the number of Mailboxes and the size of your logs. So for some users, it could be interesting to clean large log files! There were some mails pointing out to this problem on this thread. Trying a clean up of mailboxes may also help.

4. Some people who do not have Avast seem to experience a high CPU problem. For them, I think we still don't have a clear pattern... I'll try to read the messages once again later.

I hope it helps. I think I will write to the Apple senior technician officer in France whom I discussed with several weeks ago to transmit her these informations.

Regards,

Pascal.

Good synopsis, and probably correct all the way around. I also noticed an improvement when I shut down WiFi and went with just wired Ethernet. Based on the discussion, we seem to have at least two or three different 'root causes' that are giving the same symptoms.

For those who have seen improvement after shutting down part or all of Avast, but who also aren't comfortable running without protection, Avira appears to be a good alternative. It also has a premium paid version, and provides security for iOS devices and PCs, for those with mixed environments.

http://www.tomsguide.com/us/avira-free-antivirus-mac,review-2976.html

https://www.av-test.org/en/news/news-single-view/mac-os-x-under-attack-10-securi ty-packages-put-to-the-test/

Hi all,

Thanks for all your efforts to solve this really annoying behavior. At least, it shows, that I am not alone with it.

First of all some facts about my system:

* macbook pro 13" late 2011, 2,4 GHz i5, 4GB RAM, El Capitan 10.11.3;

* no avast or any other antivirus/internet security app running;

Mailaccounts:

* 1 x icloud

* 1 x MS Exchange account

* 4 x IMAP/SMTP accounts hosted at one ISP, one of these four drives mail app "crazy". If I switch of this specific one account (which is huge with many mails in many subfolders), everything is fine.

What I did:

* delete all the mail log files

* switch from WiFi to LAN

Unfortunately with no success. This all came up after upgrading to El Capitan. With Mavericks everything was fine and is fine on my iMac (late 2009).

Looking forward to any future suggestion.

Cheers,

Stephan

Are you managing any Exchange account as IMAP or are all your Exchange accounts difined as Exchange?

It is the problem I had and after redefining me Exchange account I fixed it: "https://discussions.apple.com/thread/7275988?answerId=29624796022#29624796022"

Hi,

* the Exchange account is configured/managed as Exchange (and works like a charm),

* the 4 IMAP accounts are separate accounts, linked to another but one server, one of those four runs crazy,

* no Exchange running as IMAP

Cheers,

Stephan

Hello Pascal,

Hello everybody,

Yes, thanks a lot for all your efforts to solve this frustrating problem.

And I confirm too that the problem is still there in 10.11.3...

All my accounts (9) in Mail are IMAP configured and as many of us, I had this very boring problem! :-(

And I confirm also that the "trick" proposed by Pascal was rather efficient in my case.

After just unchecking the « activate IPV6 » box in parameters for Avast mail shield and restarting my MacBook Pro, the « High Mail CPU » problem disappeared instantly, bringing me back to a normal CPU use for Mail.

Mail CPU usage decreased from 220% to about 13% during sync and nearly at 3% between sync phases (every 1/4 of hour).

There is some hours now that everything is OK. Lets hope it will last!

FYI : My computer is a MacBook Pro 15’’ RETINA End 2013 (OS X 10.11.3, 16 Go RAM, SSD 512 Go). It is connected by an RJ45 cable to my LiveBox via a Gigabit switch and I rarely use WIFI connexion!

Hoping it could help solving this problem.

Regards,

Jean-Claude

Hi Pascal:

Finally I found some time to try this. The short version is: Unfortunately it didn't work... But thanks for the suggestion!

The slightly longer version is:

I have 2 accounts, one of them causes the problem, the other is fine. So I first enabled the one that worked fine, and the CPU usage of Mail stays within reasonable values (5-15%) for as long as it takes to recreate the local folders. When that is done, Mail goes back to very low CPU levels. When I click on "Get New Mail" the CPU goes up to 5-15% for a second or two, and then drops back to less than 0.1%. So far so good.

When I enable the problematic account, CPU usage of Mail quickly goes up to 150-200% for a while as Mail recreates the local folders. (Notice that for the other account it never went above 15% during this process.) Once the process is complete, when I click on "Get New Mail" the CPU goes up again to 150-200% for ~10 s. I can live with this, but it does not look normal to me. (And I had to drastically reduce the number of messages to get it down to 10 s. Before it was ~4 minutes.)

I wonder whether this may be related to the software used by the IMAP server. The one I am having problems with uses Dovecot. The one I have no problems with is Yahoo, but I don't know which IMAP server they run.

Mariano

Dear all,

I'm new to this forum. I also have a problem with mail in el captain. I have only 2 mail accounts active: 1 Gmail and 1 IMAP account.

I experience a constant 30% CPU usage by mail and I don't have avast. Do you have any clues on what I could try to fix this?

Thanks

Nice to be a member of this self-help forum...

Seems that Mail gets its knickers in a twist when the network changes. This could well be when the laptop's closed and moved to a different network.

I've noticed this whilst messing around with some VPN settings, so swapping from the live network to my tethered iPhone and firing up the VPN. Mail goes into a hissy-fit and tries to cook the CPU. If I get bored with it and kill mail using Activity Monitor, it then takes a minute or two to die, but once dead it can be re-started and seems to work OK.

It's been going on for a long time and I think pre-dates El Capitano. Therefore it's more likely going to remain a feature.