OS X Capitan mail in combination with Avast generates high CPU usage.
It seems that Avast is the culprit application.
For more information see this thread.
Alas, the only solution seems to completely uninstall Avast.
Is Avast aware of this and / or looking into this matter?
Gerard
No. Until we get some useful info for at least reproducing the issue, there is nothing we can
do about it. Moreover, the linked thread is most probably a compilation of many problems,
where only one of them is (likely) related to Avast. Regardless of a lot of completely wrong
info there, like the “11.2 incompatability”…
I have the same problem on a 2012 MacBook Pro and intermittently on a 2012 Mac Mini with OS X Server, both with OS X 10.11.2. On the MacBook Pro, Mail checks 8 accounts (5 POP, 1 Google, and 2 iCoud). The problem ONLY occurs with one of the icloud accounts, but has become so persistent for this account that it effectively disables Mail. Taking this single icloud account offline immediately eliminates the problem, as does disabling Mail Shield in Avast Preferences. On the Mac Mini, Mail checks 3 accounts (2 POP and 1 icloud), and the problem occurs only intermittently, sometimes with days between episodes. However, when the problem occurs, it is again with exactly the same icloud account as on the MacBook Pro. No other mail accounts are affected, even a second icloud account. On the MacBook Pro, I’ve completely deleted the icloud account, then recreated it, but this did not affect the problem with Avast. I’ve now been running with Mail Shield disabled for 3 days and the problem has not reoccurred.
Are there any “CPU usage” diagnostic reports in the Console? Or any other interesting reports like crash reports?
I have been able to localise and reproduce 100%-250% CPU usage with Mac Mail open and Avast Mail Shield enabled on 3 separate Macbook Pros (2 x 15" retinas, 1 x 15" standard). All are running El Capitan and have generic mail, iCloud and Hotmail accounts set-up (not all have the same number or combo of accounts). Emails download very slowly or not at all. The Macbooks overheat.
Disabling the Mail shield and then restarting the Mac Mail app has an immediate effect. CPU drops to <5%, emails download quickly, Macbook cools down.
Side effects recently have been over-heating power-supplies and poor battery life. Makes sense as the CPU was consistently drawing a low of power.
I tried many suggestions in Apple forums to fix Mac Mail running at high CPU on the 3 Macbooks - they made no difference. Only disabling the Mail Shield made a difference. Others appear to be reporting the same.
The only change that has triggered this behaviour was the upgrade to El Capitan (both 10.11.2 and 10.11.3 are installed between the 3 machines). Whilst El Capitan may not cause it directly, it does appear to interfere through its interaction with Avast.
Hoping Avast will investigate further…
Same problem.
Same fix ie to uninstall Avast
Don’t think I have time courage to re-install and investigate.
Thank you.
I started a new thread with specific issues, including 450% demand of CPU.
Maybe this can help troubleshooting the problem.
I’m running on Mac OSX version: 10.11.1 with Mail version: 9.1 build 3096.5 and don’t have this problem.
My Avast program version is: 11.5.45630
Can someone else confirms this?
A little bit research learns that upgrading to 10.11.2 & 10.11.3, which at this moment are impacted with this problem, has Mail version: 9.2 build 3112 installed.
Source: https://discussions.apple.com/message/29547585#29547585 (the problem described in this discussions has nothing to do with this problem, but it shows a log of the Apple Mail application)
Hopefully Avast can find and isolate this problem for the impacted customer who use Avast on Mac in combination with Mail.