Slow Mail application

Posted by Pierre Igot in: Mail
June 29th, 2009 • 9:54 am

This one is a bit of a mystery to me. I have been using Mac OS X’s Mail as my e-mail client for many years now, and have slowly but steadily been accumulating an archive of thousands and thousands of e-mail messages in various mailboxes.

I am always careful to remove attachments before filing messages away (I save the attachments that I need to keep elsewhere before removing them), so that the total size of my “Mail” folder does not become unmanageable. But I do keep the messages themselves, and according to Mac OS X’s Finder I now have over 100,000 items in that folder, for a total size of over 1 GB.

Most of these messages are filed in specific mailboxes, so that my main account mailboxes (Inbox, Sent, Junk, Trash, and Drafts) are reasonably lightweight.

Until recently, this situation did not seem to be a problem for Mail, which was performing adequately on my three-year-old Mac Pro.

For some reason, however, a few weeks ago, Mail started displaying an unmistakable level of sluggishness. And when I say “displaying,” I mean it:

Mail - Loading

This is what I am now getting far more often than I would like when I am doing a very simple thing such as opening a message in a separate window to read it.

The message’s contents do appear eventually, but it can take several seconds, and there is absolutely no apparent reason for this delay.

It tends to happen more frequently when I try to open a message to read it while Mail is still in the process of sending a reply to another message. (My Internet connection is not very fast, so that can take a few seconds, even for sending a small message.) But it also happens when nothing else is going on in Mail. (I keep the Activity Viewer window open at all times in order to be able to monitor Mail’s various processes.)

This never used to be a problem in Mail, which, on my Mac Pro, was, until recently, perfectly able to handling multiple tasks simultaneously without any noticeable delay and was certainly able to open a message window and display the message pretty much instantly.

I haven’t changed anything to my settings or my hardware configuration, and there haven’t been any significant software updates that would explain such a change. And it’s also hard to imagine that, after several years of being able to handle thousands of messages without problems, Mail would all of a sudden have somehow reached a limit and lost its ability to perform at an acceptable pace.

I should stress that this is not a problem with the Mail UI itself, which remains responsive at all times. The problem is with the threads that the UI triggers.They all appear as separate processes in the Activity Viewer, with a progress bar and a “Stop” button for each (although some “Stop” buttons are greyed out and cannot be clicked on). Even the simple process of double-clicking on a message to open it in a window triggers a couple of threads that appear in the Activity Viewer.

Normally they just flash by and the message opens almost instantly. But now I see these threads stay there in the Activity Viewer for several seconds while Mail seemingly struggles to complete them (and displays the above-mentioned “Loading…” message in the message window instead of the actual message contents). I can still do other things in Mail or elsewhere in the meantime, but that is faint consolation. I don’t think I should have to wait several seconds for a message to open in a window so that I can read, especially when that message is just plain text with no pictures and no fancy “rich text” code.

I have tried various things, such as “rebuilding” my Inboxes (with the “Rebuild Mailbox…” command). But it has all been to no avail. Mail still is significantly more sluggish than it used to be when it comes to completing its various threads of activity. (Again, the UI itself is not sluggish. It’s only the threaded processes. But since pretty much everything that the user does in Mail triggers one such process, it very much affects the very usability of the application.)

Did Apple make some kind of change in the Mail code in a recent Mac OS X 10.5.x update that would have caused this problem to crop up? It’s quite possible. But it would be mighty hard to prove, especially since I don’t have a specific date for the moment this problem started happening to me on my Machine.

In all likelihood, what will happen is that I will have to live with this new problem for a few more months, and then Snow Leopard will come out with its many promised improvements in performance, and things will be better again. At least that is the best I can hope for at this stage, I am afraid.


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