All Posts by Date or last 15, 30, 90 or 180 days.
also by Lloyd: photography and
Thank you for purchasing through links and ads on this site.
diglloyd Deal Finder...
Buy other stuff at
Blazing-fast PCIe storage for Mac Pro Tower

macOS Sierra: Severe Apple Mail Performance Problems

Apple Mail in macOS Sierra:
pegs CPU for 30 seconds or so

New Apple Core Rot, and in a key area of functionality, at least for MPG.

Apple Mail in macOS Sierra has severe performance issues (and continuing bugs), just as in El Capitan and Yosemite. But is is far worse now, which speaks to the continuing incompetence by the programmers working on Apple Mail. Performance was notably degraded with the arrival of El Capitan; it seems that Apple is trying to engineer in bad performance. I think it is related to badly done search algorithms, similar to the performance losses in save and open dialogs. Continuing Apple Core Rot.

Clicking on my Sent mailbox (and others) results in delays of up to 30 seconds in showing the mailbox, along with multiple rainbow beach balls. The system has had ample time to do whatever it is it does after a system upgrade. Then trying to open one message may take another 20 seconds. Apple mail pins a CPU or more during this time.

The mailboxes have thousands of messages... a trivial task for software to manage if designed competently. If the issues are indeed related to the number of emails, then one half-assed and unpalatable solution may be to archive older mails.

The behaviors are so troublesome that MPG may be forced to abandon Apple Mail and to seek out an alternative mail program. One reader suggests Airmail.

Other mail problems:

  • As usual, Apple requires non-reversible “updating” of stored mail. A not so nice move by Apple (every release!), since there is no going back.
  • Certain Apple Mail preferences get whacked, including ones useful for security, so re-check mail preferences. This Apple Mail behavior violates good mail hygiene in a security sense (e.g. enabling loading of remote content in messages, removal of the display of custom mail headers, etc).
  • The password for certain types of mail accounts get removed, and they must be re-done (this happened in El Capitan also).
  • VIP senders remain 100% broken (non functional), just as in El Capitan.
  • Unread mail icon shows 8 unread messages, but there is only one shown.
  • Apple Mail beeps sporadically for no apparent reason.
  • Switching between mailboxes can take 30 seconds.
  • Messages can take 10-30 seconds to draw (blank message window). These are messages on the local SSD, not remote messages (nothing to download).
  • Frequent rainbow beachball hangs, often for several seconds.
  • Half-second delays after deleting an email.
  • Search is almost unusable even for the simplest one: multi-second delays.
  • Half-second to a second or longer pauses while typing a short email.
  • Many more sluggish performance problems.
  • Unable to copy and paste with some types of content that I have done many times before. This is an all-new bug. Repeatable, even after quitting and restarting mail.

Apple Mail is a nearly unusable disaster in macOS Sierra aka clusterf**k. Perhaps it works fine with iCloud or diddling around with a few dozen messages, but it is too slow to be usable; everything I do is subject to multi-second delays. Just about everything in macOS Apple Mail involving selection or search or delete or so on has multi-second delays and pins a full CPU core at 100% during that time. Searches and/or examining my Sent mailbox can take up to 30 seconds to respond. This is not a one-off issue, but a constant problem. Never before has Apple broken Apple Mail this badly; It looks like I am going to have to abandon Apple Mail.

The sheer wanton incompetence necessary to code, let alone ship this excrement to customers is mind boggling.

The good news (should I have to switch), that Spam Sieve (which I consider essential) supports many mail clients. The bad news is there might not be any rock solid email clients to switch to, see comments below.

Apple Mail in macOS Sierra: frequent rainbow beachballs while pegging a CPU core

Possible improvement, suggestion by Arne E

Mail does seem to become laggy on its own after a certain time, and until now rebuilding the Mail index has always helped. It doesn't become OS9-snappy, but at least I don't have to wait 10 or 30 seconds for a message to appear. Don't know if this solution works in Sierra, but you should test it.

The vacuum command will rebuild the email database, not the mailboxes (see below). Makes me feel like I’m running Windoze or something, that is, having to crap like this that ought never need to be done by any end user.

  1. Quit Mail
  2. In Terminl, paste this command and hit return:
          /usr/bin/sqlite3 "$HOME/Library/Mail/V4/MailData/Envelope Index" vacuum
  3. Restart mail.

I’ve tried this. Still getting spinning beachballs, but it may be more responsive. TBD.

Daniel M writes:

That’s why I moved to Outlook for Mac since early this year. I can’t stand the poor performance of Apple Mail. I have an IMAP professional email hosting, and an Exchange Online Office 365 and both have a custom domain. Apple mail handles both accounts very poorly especially the exchange account. It doesn’t matter if the mailbox and folders contain tens of thousands of messages because if it is done correctly the system can handle this task very easily. I also encountering slowing down when loading folders, and at the same time, the unread counts are very unreliable.

Surprisingly, Outlook performs really well. It is fast responsive and handles various types of accounts very well.

MPG: I run my own mail server also, but it is POP3. One reader suggests Airmail as the client, see below.

Mark E writes:

I’m surprised you are still using Apple Mail. Maybe you could go into what features keep you in Apple Mail. It did get a lot better a few years ago, but then stagnated.

It seems obvious that the new Apple won’t put any serious development resources to freebie apps. If it sends and receives email, it’s good to go. It wouldn’t surprise me to hear that Dev did the testing as well. :^}

I’m using Airmail and find it extremely robust.

MPG: looks I may have to move to something like Airmail.

Martin D writes:

The mail situation just keeps getting worse and worse and I don’t know what to do.

I’ve tried AirMail. It has lots of problems, too… different problems.

It’s as if there’s a global conspiracy to bury email unusable.

MPG: (I know Martin and trust his feedback)—I don’t know if I can tolerate AppleMail much longer, but if AirMail has issues I’m hosed.

Mike C writes:

I read your post regarding Apple Mail bugs and potential third-party mail apps. I've been using MailMate on Snow Leopard for several years and am mostly happy with it. As a default, it blocks external content links in messages, and the user has the option to load the content or not upon opening the message.

The developer is one guy against the giants; I think he's doing a pretty good job.

MPG: another potential replacement candidate for Apple Snail Mail. It’s useless to me however, because it is an IMAP client only, not POP3.

Deals Updated Daily at B&H Photo
View BEST Deals Right Now
B&H Deal ZoneDeals by Brand/Category/Savings
Deals expire in 15 hours unless noted. Certain deals may last longer.
$2299 SAVE $500 = 17.0% Canon EOS 5D Mark III DSLR in Cameras: DSLR
$2297 SAVE $800 = 25.0% Nikon D750 DSLR with 24-120mm in Cameras: DSLR | Terms of Use | PRIVACY POLICY
Contact | About Lloyd Chambers | Consulting | Photo Tours
Mailing Lists | RSS Feeds | Twitter
Copyright © 2008-2017 diglloyd Inc, all rights reserved.
Display info: __RETINA_INFO_STATUS__