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Level 1

41 points

Mail.app Ridiculously High 100 percent CPU and Memory Usage

Mail.app (v. 8.2 on 10.10.4) regularly uses 100 percent of my cpu and memory. This is on a beefy Mac Pro with 64 GB RAM ⚠:

Mail.app is essentially unusable because of this. It takes 30 minutes to encrypt and send a simple SMIME email. Large (a few MB) attachments exacerbate the problem. The mail account is on an Exchange server. I have hundreds of SMIME certificates in my keychain. This is a lot, but not too much, and is really a typical enterprise environment at which Mail.app is failing.

Any suggestions to fix this?

I'd switch to a different enterprise mail client if I knew of a better option. Any help either fixing Mail.app or a recommendation for a capable enterprise mail client on OS X would be greatly appreciated.

Posted on Aug 3, 2015 3:03 PM

25 replies

essandess Author

Level 1

41 points

Aug 3, 2015 5:52 PM in response to Linc Davis

And I've posted how to create your own S/MIME certs. I've never had a problem with those, and I'm not sure if the issue is with the cert or the scale of the PKI.

Linc Davis

Level 10

209,547 points

Aug 3, 2015 6:07 PM in response to essandess

That might be OK on a local network, but you can't expect everyone to trust your self-signed certificate. That would defeat the purpose of S/MIME.

cdhw

Level 4

3,588 points

Aug 3, 2015 6:13 PM in response to essandess

Various suggestions in this thread.

https://discussions.apple.com/thread/6611183?start=90&tstart=0

essandess Author

Level 1

41 points

Aug 3, 2015 6:24 PM in response to Linc Davis

Linc Davis wrote:

That might be OK on a local network, but you can't expect everyone to trust your self-signed certificate. That would defeat the purpose of S/MIME.

Meh, TOFU.

That's exactly how a lot of enterprise PKI works anyway.

We can all improve this after the EFF launches their free CA.

essandess Author

Level 1

41 points

Aug 3, 2015 8:24 PM in response to cdhw

cdhw wrote:

Various suggestions in this thread.

https://discussions.apple.com/thread/6611183?start=90&tstart=0

Thanks. I went through the thr ad and tried all the suggestions, but no luck. I see others with the same issue with Exchange. This is obviously a serious bug that's been around for a long time.

Aug 7, 2015 1:30 PM in response to essandess

I'm experiencing the exact same issue in both Mavericks and Yosemite. I upgraded to Yosemite in hopes that it would solve the issue, but it did not...

I don't have anywhere near as many S/MIME certs (<50). Sending S/MIME with attachments is what kills Mail on rMBP.

essandess Author

Level 1

41 points

Aug 7, 2015 2:20 PM in response to broberts666

Yes, it's been an issue since at least Mavericks, and I doubt there's a fix.

Please take a moment to file a bug report.

essandess Author

Level 1

41 points

Aug 7, 2015 2:33 PM in response to Linc Davis

The EFF's Let's Encrypt has scheduled signed certs with their root CA in mid-November. I'm hoping the EFF certs will work easily with Mail.app, OS X Server, and iOS. There's lots of OS X and iOS enterprise bugginess that I hope Apple devotes some effort to fix.

essandess Author

Level 1

41 points

Aug 17, 2015 1:18 PM in response to broberts666

Update for 10.10.5: With this update the cpu usage is still 100% and Mail.app crashes for large attachments with signed and/or encrypted emails, but I no longer see the memory leak.

Oct 27, 2017 8:00 AM in response to KiltedTim

Glad to see that this problem is still kicking almost 2 years later.

Mail.app Ridiculously High 100 percent CPU and Memory Usage