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Mail running +100% of my CPU!

20655 Views 37 Replies Latest reply: Feb 24, 2014 3:24 PM by Kepar RSS
  • Charley Armstrong Calculating status...
    Currently Being Moderated
    Aug 12, 2011 5:20 AM (in response to Mac OS 9000)

    32-bit mode doesn't seem to change the amount of CPU time being used - still in the 110+% range when browsing - very slowly - through RSS feeds in Mail.  Each message seems to take seconds to load, unlike SL which seemed to take milliseconds.....  Unworkable. 


    Interestingly, the MS Outlook client reads mail messages faster than Mail does.

  • Robert Walch Level 4 Level 4 (1,275 points)
    Currently Being Moderated
    Aug 12, 2011 8:37 AM (in response to Ferris16)

    I am still seeing 100% CPU with Mail and short battery life.  I have tried the following with no improvements. 


    1. Reset the P-RAM -  Started up by holding down Option / Command / P / R


    2. Reset Battery -  held down CTRL / Option / Shift / Power Button for over 10 secs.  Then started up.


    3. Did a verify HD - and found errors and did a fix - by starting up and holding down Alt Key and using the recovery disk. 


    So even though in step 3 there were errors and I fixed them - then restarted and let the spotlight index run its course before opening any other apps.  When I did finally Open Mail - it was running at 100% and has been so for the past few hours. 


    Time to make an appointment at the Genius bar and see what they say - I will update after my appointment.


    I have updated to every major new version of OS X going back to 10.0 and without a doubt this "update" to Lion is the worst and only one I ever regretted doing. 

  • Charley Armstrong Level 1 Level 1 (0 points)
    Currently Being Moderated
    Aug 19, 2011 12:02 PM (in response to adamshore)

    I would say that you migated the problem, but did not fix it.  For me, I am maxed out at 4Gb of RAM, so no help there.  My machine runs 24/7, so reindexing *should* be complete.  I also have decided to move RSS feeds to another application - which btw is lightning fast - and wait for Apple to fix the RSS issue.  Mail still uses 100% of CPU when quickly scanning my mail messages, and will bog down after previewing several messages in quick sucession. 10.7.1 has not corrected any mail issues as far as I can tell.

  • Monkey Cat Calculating status...
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    Sep 1, 2011 3:11 PM (in response to adamshore)

    This worked for me:


    Disable all of your mail accounts and restart Mail.


    1. Choose "Preferences..." from the "Mail" menu

    2. Choose the "Accounts" pane

    3. For each account:

    3.a. Choose the "Advanced" tab

    3.b. Un-check the "Enable this account" checkbox

    3.c. When you switch to a different account or try to close the preferences window, click "Save" when prompted to save changes

    4. Restart Mail


    After restarting Mail with no accounts enabled, it shouldn't use any CPU at all -- there are no messages to display!


    Re-enable accounts, one by one, until the CPU usage is back at the previous levels (> 100%). Note that Mail will always consume a good bit of CPU immediately after you launch it while it syncs with the mail servers.


    Once you've found the account that causes the CPU usage, go to each of your mailboxes and folders for that account and choose "Rebuild" from the "Mailbox" menu. Alternatively, you can just delete the account from Mail completely and re-add it. If you have multiple accounts, note that there may be more than one account that needs this treatment. As an extreme measure, you can delete ALL of your accounts from Mail and re-add them (or rebuild the mailboxes for ALL of your accounts). In my case, the first mailbox I rebuilt (the Archive mailbox in my MobileMe account) did the trick.


    This will cause Mail to re-download everything in the account. I think the CPU usage might be caused by something that was messed up with the account was initially downloaded and/or indexed. Resetting that (by rebuilding the mailboxes) fixed the problem. Mail is back down to 1% CPU when idle, even with approximately 5 GB of mail on a collection of IMAP accounts.


    Good luck!

  • Monkey Cat Level 1 Level 1 (0 points)
    Currently Being Moderated
    Sep 1, 2011 3:25 PM (in response to Monkey Cat)

    After doing the steps above, I experienced the 100% CPU issue again. However, I was aware of which messages I had recently viewed before the CPU usage started creeping up. I rebuilt the mailbox containing those messages, and the CPU usage went down again. And then went up again when I viewed a certain message (in my case, the message had a large attachment). I deleted the message (and then "emptied the trash" with Command-Shift-Delete), rebuilt the mailbox again, and all is quiet once again.


    So I guess rebuilding the mailbox doesn't actually fix anything, it just resets the state to where Mail isn't touching the problematic messages. Once in that state, you can find the messages, delete them, and then things are happy.

  • Bardo Calculating status...
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    Oct 13, 2011 7:19 AM (in response to Mac OS 9000)

    Thanks "Mac OS 9000"; running in 32-bit mode worked for me. I went from 98-100% CPU usage to 8-10%. I can breathe again!

  • coldcommuter Calculating status...
    Currently Being Moderated
    Nov 8, 2011 6:52 PM (in response to Bardo)

    I've had similar issues - Lion Mail was incredibly slow to load and hogged in 200%+ of my CPUs on my late-2009 iMac 27. Tried the other solutions without success (or maybe they were contributing factors to my eventual success )


    Then I happened to hover over the RSS feeds and noticed that it had created feeds for each and every folder in my mailbox. Once I deleted those - which took a while, by the way - Mail loads and responds in a timely manner, with 64 bit mode being considerably faster than 32 bit (as I would expect). A welcome relief.

  • Mac OS 9000 Level 2 Level 2 (270 points)
    Currently Being Moderated
    Nov 8, 2011 8:58 PM (in response to coldcommuter)

    Yeah, having a million RSS feeds is a common problem. Sometimes, the only problem is 64-bit mode for some reason (well it probably is due to some other problem, and 32-bit isn't affected).

  • hnewman Calculating status...
    Currently Being Moderated
    Jan 3, 2012 2:40 PM (in response to Mac OS 9000)

    I have seen my CPU usage for mail go over 200% on Lion 10.7.2.   I have a large inbox with several thousand messages.  Should I try archiving some of these?  Is there a way to use mail like I did in Snow Leopard without all of the conversations?  All of my applications are running much slower after about 2 hours including Pages, Firefox, Numbers.  Any suggestions are welcome.

  • Andreas Carlsson Level 2 Level 2 (235 points)
    Currently Being Moderated
    Jan 9, 2012 12:22 PM (in response to adamshore)

    I have the same problem. 8 GB RAM, no RSS, problem arrived with Lion. I have done everything that's possible within the normal lifespan, to no avail.


    If I come close to the computer (a 2010 MBP) I know if Mail is started, because the fans are blowing. It's redicilious!


    I have reported this to Apple at the Feedback page. I hope they fix it soon.


  • druidb Calculating status...
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    Apr 9, 2013 8:13 PM (in response to Andreas Carlsson)

    Does anyone know if this has been fixed by Apple yet? Or, any easy fix? I've tried so many of the suggestions offered (rebuild index, delete account and start fresh etc..)



  • Andreas Carlsson Level 2 Level 2 (235 points)
    Currently Being Moderated
    Apr 15, 2013 12:57 AM (in response to druidb)

    I don't think so.


    I got rid of the problem after a clean OS X install and no importing of my old user. I have saved my old mbox files elsewhere on my drive.

  • ramarsha Calculating status...
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    May 18, 2013 12:57 PM (in response to adamshore)

    For us the fix was VERY VERY difficulty to find... but once identified very easy.


    Our symptoms were Mail consuming 100+% CPU and crashing when the accounts tab in the mail prefs was clicked... our first clue!


    I tried every iteration of deleting .plists, repairing permissions, reinstalling systems, etc. I started pouring over the console logs and examining the processes in the activity monitor...


    In the end the fix was to run keychain first-aid. Yup, that was it. Works perfectly now. *chagrin*.


    PS- Thanks a lot PKard 1.3 !! uninstalled; bye bye.

  • A.dickey Level 1 Level 1 (0 points)
    Currently Being Moderated
    Aug 6, 2013 2:48 PM (in response to Charley Armstrong)

    Run Key Chain ~ FIrst Aid


    You may find a list of account related items in red text


    Dont know how or why but First Aid it fixes it immediately


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