Q: High Mail CPU with El Capitan

As with other people on this thread I've got the same Mail issues and have tried the various solutions (posted about on this thread), but so far to no avail. Just last week I noticed that the process which is hitting the highest CPU (and which is top of the activity list when the beach ball is spinning) is accountsd - anyone know what this does in relations to the other Mail processes like Mail, mds_store etc? I've got a similar multi-Google-IMAP-account situation to a lot of the people also experiencing this problem.

I have the feeling that not all on this thread are suffering from the same problem. Although my own issue appears to be common to many. I have 4 email accounts - 3 IMAP and 1 Exchange. In general its a particular IMAP the causes the problem. The process that hits high CPU %ages is 'Mail'. I am very glad to read that Apple are active on the problem. As an ex-outlook user from <2000 to mid 2012 I can say that my conversion to Mac has been a good experience - other than Mac Mail which has caused suffering to outweigh the various other benefits. I have been searching for a link that correctly described the current issues and this one is the closest I have found - so, Apple, I am also at you disposal. Currently, the best 'fix' I have found is the deletion of the troublesome IMAP account and then its recreation - this typically gives relief for a shortish number of days before the high CPU issues returns. Usually it comes back softly where restarting the Mail program can clear the problem for hours but it becomes increasingly hurtful from then on. 

The problem is definitely NOT (only) related to Exchange as I mis-stated earlier.

My largest email account is an IMAP account, with lots of folders, containing over 7400 emails in history seems to be another culprit.

I now have my hopes up because mail version 9.2 (3112) has just been rolled out.

Deleted the emails and re-downloading them as we speak.

Gerard

I've seen this issue occur before due to corrupted mail logs.

1. Quit the Mail app

2. Open Finder, select Go from the menu bar then Go to Folder.

3. Go to ~/Library/Containers/com.apple.mail/Data/Library/

4. Move the Logs folder to the Desktop

5. Launch the Mail app

If the issue is resolved, trash the Logs folder

If the issue is not resolved, restore the Logs folder to the original location

Hi @GerardFromUlrum - I've got 9.2 (3112) and unfortunately it hasn't helped.

Hi @agnew50 - with me, when I switch to Mail from another app or often when switching between open Mail windows (if I'm composing a mail and switch back to the main app window), accountsd hits 100% and I get a beach ball. Then the beach ball goes, I'm able to use Mail, but the CPU for Mail.app is high for a few seconds and the app is sluggish.

Thanks for the tip, chroot!  I just did this and it seems to have helped.  For those who are interested / affected, I'll report back here if it returns to its former behavior, but I'm cautiously optimistic after the immediate and dramatic change, which has been holding steady now for over an hour.

After killing the log folder, CPU is bouncing between 1 - 15 percent utilization with the CPU temperature in the 50 - 55 degree range and the fan under 2000 rpm, where before the stats would jump to 50+ percent on the CPU, 85+ degree temp and fan running 6000+ rpm the moment I launched Mail.

I have a MacBook Pro Retina, 15-inch, mid 2014 with 16 GB of memory. I am running 10.11.2

I just wanted to add that I just started having this issue as well about a week ago. In activity monitor CPU jumped to 267.7% and it is making my fan come on. I spoke with apple yesterday by chat and by phone. She said that it could not be the mail app that is causing the fan to come on but when I shut down the mail app and the CPU slows down the computer goes back to normal.

Here is the other weird thing is that I am running two accounts through mail. Exchange account and iCloud account. When I deleted my iCloud account yesterday it seemed to run normal. Today I added the iCloud account and it started having the same issues

Tried that, no significant difference yet.

(but just had mail rebuild the culprit account)

Similar problem on 2 Macs, so not a hardware problem. When I move to El Capitan, I decided to completely recreate/resynch my mail. So deleted old one, and started resyncing. CPU consistently at 200+%, on both Macs.

- iMac i7 24Gb with Fusion drive

- MacBook i7 16Gb 1TB SSD

They started 'building' their mail around December 24th, and still going... I'm checking the size ('get info') of mail directories on both devices, and it's still growing. Size is about 24Gb, 380 000 items. (3 IMAP accounts, 1 iCloud, 1 gmail)

I hope that it's so heavy because it is still building (although this shouldn't take weeks on such a heavyweight machine...).

Outlook? No way - been there done that. Had so many issues that I moved away from Outlook for Mac.

Apple looking at this problem? I'm not naive... Mail has always been among their weakest points, and they're pretty deaf wrt user feedback. I'm pretty blunt, though a full blown Apple adept and shareholder, but unfortunately listening to their users for 'tactical' issues isn't amongst their better assets.

@Apple - pls prove me I'm wrong. Very willing to help give feedback to get this issue fixed.

Thanks

I got relief from all issues from another thread ("Mail keeps crashing…", altho' I never had crashes, only ridiculously slow 'downloading'.)

Here's my reply from 12/21. Mail has been fine since.

grettaDec 21, 2015 6:48 AM Re: 10.11.2 El Capitan: Mail keeps quit and asks for rebuild
Re: 10.11.2 El Capitan: Mail keeps quit and asks for rebuildin response to iggigg

  another good thread     

I did as suggested there:

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

- quitting the app;

- deleting 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; How to Reset NVRAM on your Mac - Apple Support

- 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%, Not sure about 'memory controller', but this doesn't seem to indicate that Mail would be affected.)

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.

Found my high CPU% was being caused by Avast Mac Security.

Uninstalled using Avast's instructions (don't just put it in trash, you'll have to reinstall it and follow these instructions.)

Symptoms were 150-300% CPU, hanging message downloads and the following error messages in Console logs.

1/5/16 2:16:10.224 PM com.avast.proxy[556]: Defective IMAP response!
1/5/16 2:16:36.761 PM com.avast.proxy[556]: Error parsing mail file: parse error!

Now I have immediate downloads and 0.0% CPU on mail app.

Will have to see if this is a long term fix but removing Avast helped me.

I also have Avast...interesting.

Avast is also on my Mac, and while it may possibly be involved in running up the CPU even more on systems that are having the issue, my experience would suggest that it is not the actual root cause.  After doing chroot's log folder fix several hours ago (per my previous post above), I'm still working fine (lower CPU / temp / fan) -- even though Avast is still up and running as I write this.

The logs show Avast directly interacts with mail, parsing it likely for security risks and evidently for what it considers good responses.  Therefore if it was to act up it could indeed have ramifications on the Mail app.