Q: High Mail CPU with El Capitan

I've disabled the Avast Mail Shield in the preferences. Will post the result.

I also have Avast Mac Security. I've disabled the Mail shield too.

I only saw relief after actually uninstalling it.  Disabling didn't have an effect on my machine.

Interesting, Avast also running here...

Could we be nearing in on target?

Thank you guys!!!! I had avast too. I uninstalled it and the problem is gone. Very nice observation! Thanks again.

Not solved on my side. Not running Avast, but having problems on both machines (see former post)...

everyone?  My Mail, when idle, uses 0.0 - 0.2% of CPU.

When checking (9 accounts, most IMAP) it goes up for a bunch of seconds.

All,

I had Avast running, disabled it on Mail and my problem went away.  I have uninstalled the program and am good to go.  Thanks for the info.

I am also using Avast - looks hopeful .... encouraging.

Since I rebuilt my offending IMAP account yesterday I don't expect to see the problem for a while. When it does return I will disable / delete Avast and see what happens.

Out of curiosity i went to avast's web page.

After wasting several minutes i could find no indication of whether its compatible with OS X.11

Since such protection is largely needless on a Mac, i would nto run it. why do you?

Grant

While OS X is inherently much more secure than the-operating-system-that-shall-not-be-named, the only truly invulnerable computer is one that is BOTH air-gapped (not connected to anything else) AND completely shut down.  Viruses that target the Mac platform are relatively rare at the moment, and they're generally not able to do as much damage for now, but both of those circumstances are beginning to change as Apple's market share continues to increase.

If you're very disciplined in your browsing and e-mail habits, your Mac can (probably) survive a bit longer without protection, but the time is rapidly approaching when a really good suite of security software is just as necessary on OS X as it is elsewhere.  I personally believe that time has already come, so I'm continuing to run Avast for now.  If that product proves to be a major player in the mail issue and I end up having to ditch it, I'll be running another product immediately.

And for whatever it's worth, I continue to maintain that, while Avast might be making the problem worse on some of the systems that are running it, I don't believe it's the actual root cause of the issue.  My system and my wife's are both running fine with Avast up and fully operational (including Mail Shield), and there are several folks on this thread who are continuing to have problems with Mail, even though they've never installed Avast.

Hello,

The problem you experience is very similar to the one I have described in your forum. You can have a look at my posts on this forum.

There is something wrong with Mail: Apple acknowledges it and is investigated (several people here, including me, have been contacted by Apple to perform a diagnostic on their system). So far no solution has been found and therefore, I encourage you to identify the mail account that causes the runaway and to use another mail program to consult it.

Regards,

P. Degiovanni.

Hello,

Thanks a lot for this very interesting information. I'am one of the person who have experienced the Mail runaway (see my posts on this forum). The problem happens on one of my computers (a Mac Mini) with one of the IMAP accounts whereas it does not happen with a laptop, same OS version, same Mail version, same IMAP accounts.

However, my Mini runs Avast whereas the laptop does not run it !

So I'am starting some test: I have stopped Avast Mail agent for the moment and reactivated the IMAP account that makes Mail use all CPU. Usually, it takes two to three days before the problem starts again. So I will complete this Mail within a few days to give you the result of this test.

Regards,

P. Degiovanni.

So far so good after disabling Avast mail shield . Fingers crossed.

BriPhil says:

While OS X is inherently much more secure than the-operating-system-that-shall-not-be-named, the only truly invulnerable computer is one that is BOTH air-gapped (not connected to anything else) AND completely shut down.  Viruses that target the Mac platform are relatively rare at the moment, and they're generally not able to do as much damage for now, but both of those circumstances are beginning to change as Apple's market share continues to increase.

If you're very disciplined in your browsing and e-mail habits, your Mac can (probably) survive a bit longer without protection

... and i wholeheartedly agree with both.  Sadly, the first is correct, we have been safe only because we have not been worth targeting. now we are.

Happily, the second remains true too. Avoid dubious sites, never say "ok" to anything, set OS X to ask for permission before instilling anything, don't follow suspect email links, and you will be safe 99.something % of the time.

I have yet to see active security software that was not trouble - on either platform.  A check, like Malware bytes, that you run, is typically innocuous.

And i just updated my 3rd machine to X.11.2 with no issues, and am typing this on it.  As to mail, i have a gaggle of IMAP accounts.

Grant

ps: strangely, firefox only showed the first 4 pages of this thread. Safari shows them all.