High Mail CPU with El Capitan

Hi:

Just entering here cause I have the same problem. (Yes, after upgrading to El Capitan, Mail fires up to 200% CPU for a few minutes, and repeats that each time I check for new emails.)

I tried all the suggestions here (including removing log files, rebuilding/reindexing/synchronizing, changing several settings in Preferences > Accounts, removing and recreating the accounts, completely uninstalling Avast, etc.), but things did not change. I even created a new user and recreated the accounts from scratch, to no avail.

The problem appears to be related to an IMAP account that has ~1500 mailboxes, since it goes away when I disable that account. I am not an IMAP expert, but from the log files it appears as if each time Mail checks the account it loops through and checks each of the 1500 mailboxes over and over again (I can provide parts of the log files if that is of any use). I would have expected that some "flag" would tell the program to check only those mailboxes that did change.

What about those here still experiencing the problem? Do you also have an IMAP account with lots of mailboxes?

Thanks,

Mariano

1500 mailboxes?

And that put no load on Mail with Yosemite, but did with El Cap?

I too had this problem, it was my iCloud email account that would send the CPU into overdrive. I tried many of the fixes listed in this post. None of the provided a lasting fix, UNTIL I disabled the Junk Mail Filtering. Mail>Preferences>Junk Mail>Uncheck the Enable Junk Mail Filtering. I have not had the runaway CPU problem since.

I used email clients on an iPad, iPhone, 2011 MacBook Pro, 2014 MacBook Pro. Disabling the Junk Mail Filtering finally fixed the problem. I hope this works for some of you.

Hi Grant:

Indeed, Mail worked fine with Yosemite (and all previous versions since I have a Mac, ~2010) on this account. I believe the number of mailboxes should not matter for IMAP, since the client should not check them all, but only those that have been flagged as changed. (But I am not an IMAP expert. And the reason I have so many mailboxes is that I keep copy of all mails per sender.)

For example, I just installed Postbox 4 (demo) and, contrary to Mail, it works fine with this account: When I check for new mails, Postbox takes ~15% CPU for less than a second (Mail takes ~200% for a couple of minutes), and then drops way below 0.5%.

Hi Mike: I just tried disabling Junk Mail Filtering, but nothing changed... Thanks anyway for the suggestion!

Hello,

Having disabled the Mail agent for Avast, I can tell you about my own experience.

What does not happen anymore is a permanent high use of CPU which never stops.

What still happens is that sometimes, Mail uses high CPU for a limited time but this used to be the same before the problem occurred. This of cours depends on your computer and on the number of mail account it uses as well as number and sizes of mailboxes within each account. Nothing surprising and nothing pathological here.

Regards,

P. Degiovanni.

Hi Pascal:

Thanks for sharing that. I also uninstalled Avast completely, but my case is likely different from yours. Check these numbers:

Mail: When I check for new mail, Mail stays 4 minutes (I timed it) at 100-200% CPU. The program becomes very slow and unresponsive (a lot of spinning wheels). This happens *every* time Mail check for new mail on the server.

Postbox 4: When I check for new mail on the same accounts, Postbox uses ~10% CPU for 2 seconds.

This is a big difference.

As I wrote earlier, from the log files, it appears that Mail is checking (and updating status, flags, etc.) of all 1500 mailboxes (a.k.a. folders) on the IMAP server each time. The log files of Postbox do not show this activity.

Cheers,

Mariano

I would like to share my good news.

I had the typical very high CPU usage (about 160%) with MAIL and last friday I stated to play with my three mail acoounts: google, exchange and generic IMAP. I had Google account as "Google" type and the other two as generic IMAP (include the exchange account).

After activating and deactivating different "mail reception" options, I realized I had the problem focussed on Exchange account. Then , I removed the exchange account (that it was confiugured as generic IMAP) and I created it as "Exchange" and I used standard Exchange connection in my organization ("External server" = "/EWS/Exchange.asmx" , "Internal Server" = "/ews/exchange.asmx"). Since then, and after finishing automatic mail folders synchronization, I have had no more problems with Mail and CPU. I am already observing the system beacuse I have read that other people have deteced problems some days after. I applied it on Friday January 8th, and it is working (about 0,5% CPU usage). In this account I have about 40.000 mails in different server mail folders and about 5000 mails in "input" folder.

If I see any change in close future, I will communicate in this foro.

Aside from outlook, are there any other alternative mail clients to use whilst Apple get around to fixing mail? It's obviously OSX.11/elcap broken where the mail account is used for several accounts.

Is it possible to use the old OSX.10/yosimite mail client without upgrading from elcap to yosimite?

Postbox (https://www.postbox-inc.com/) seems to work. You can use the demo version for 30 days, and hope Apple solves the problem in the meantime. As to your second question, I don't know. I looked a bit for that option as well, but it seems the only way to use the old Mail is to downgrade to Yosemite.

I too had 100 % CPU usage with Mail trying to download old messages. I read many forums to try solve this problem. It took me two months of twiking in all directions until I moved to Airmail2 which worked fine but which I did not like too much. I went back to Mail and experienced the high CPU usage until I uninstalled AVAST and moved to AVIRA. Since the I had no more problem and Mail nice and fast...I know that for other users this trick did not do the job but for me and others it did!

Glennny2Lappies:

Aside from outlook, are there any other alternative mail clients to use whilst Apple get around to fixing mail?

--> several - Thunderbird, outlook, others. But have you disabled anything that may be interfering and re-created your accounts?

It's obviously OSX.11/elcap broken where the mail account is used for several accounts.

--> while i sympathize with your frustration, for general understanding, this statement is not correct. I -- and many, many others are similar -- use Mail with ~ 10 various email accounts - mostly IMAP with zero problems. Why is yours different? Logic dictates that should be your focus.

Is it possible to use the old OSX.10/yosimite mail client without upgrading from elcap to yosimite?

--> no.

Hi Grant:

It is true that we don't know whether Mail in El Capitan is broken or not. I can tell you, however, that on the same set of IMAP accounts Postbox does not take the CPU that Mail takes. (See my previous posts with numbers.) This could mean that Mail strictly adheres to the IMAP protocol but the protocol is not meant to deal with cases like mine with so many folders in one account, whereas Postbox does not adhere to the protocol and for that reason it works. In that case Mail would not be broken. Since I don't know how Mail/Postbox are written I cannot tell.

It is however worth mentioning that Thunderbird and Mailmate also work fine in my case. While this is not a proof, it suggests that something is not proper in Mail.

Cheers,

Mariano

rodrixtina wrote:

I would like to share my good news.

I had the typical very high CPU usage (about 160%) with MAIL and last friday I stated to play with my three mail acoounts: google, exchange and generic IMAP. I had Google account as "Google" type and the other two as generic IMAP (include the exchange account).

After activating and deactivating different "mail reception" options, I realized I had the problem focussed on Exchange account. Then , I removed the exchange account (that it was confiugured as generic IMAP) and I created it as "Exchange" and I used standard Exchange connection in my organization ("External server" = "/EWS/Exchange.asmx" , "Internal Server" = "/ews/exchange.asmx"). Since then, and after finishing automatic mail folders synchronization, I have had no more problems with Mail and CPU. I am already observing the system beacuse I have read that other people have deteced problems some days after. I applied it on Friday January 8th, and it is working (about 0,5% CPU usage). In this account I have about 40.000 mails in different server mail folders and about 5000 mails in "input" folder.

If I see any change in close future, I will communicate in this foro.

Confirmed. Finally it is working for me!!!

That suggests only that the problem lies with either 3rd party software incompatibility ( which has been rampant here) or a corruption of settings (which has also been true for at lest a half-dozen i've watched).

Yes, it could be a fundamental problem, but then why are 99.9%+ working fine? Software is not inconsistent.

Mine works with yahoo, Google, 3 universities, VFEmail, my corporate mail, exchange, and two private IMAP servers all at once.

QED.