Q: High Mail CPU with El Capitan

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.

That would solve it. Bat not for me, I need  to be able te acces these mails at home as well as at work...

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?

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.

Hi,

the same here, mail eats CPU and RAM full load, fan on max speed, the whole system becomes very slow and then mail crash after a while. After update to 10.11.2

I'm have to using web base to check 6 email account every 5 minutes

Exactly the same problem with 2012 macbook pro retina. Fan is always on if mail app is on. Weird!

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.

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.

+1 This issue!  Same on 2013 MBP

It has been quite traumatic but finally no other option that moves to Outlook for MAC.

It is not great ( no so well integrated in MAC universe) but continous 5% of CPU. Almost nothing.

One day may be I will come back.....or not.

Same issue here on i7 mac mini with El Capitan. The mail application pushes CPU into overdrive resulting in loud fan (which I never normally hear). Only solution is to quit the mail app.

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…