Outlook Mac high CPU usage: possible fixes

Ian, a MacCrazy reader writes:

My MacBook Pro (2.66 GHz, 8 GB RAM, 500 GB HD, OSX Lion 10.7.4) started to be very hot and noisy (fan) immediately after I installed the Microsoft Office for Mac Service Pack 2 (14.2) update specifically whenever I ran Outlook, despite no problem with Outlook prior to this. The CPU activity showed that Outlook was using approx. 90% of CPU. After 5 days I removed MS Office completely and reinstalled it without updating to SP2 and everything was fine again. Then some days later, when the fix was released for SP2 (14.2.1), I again installed it, and then the problem of excessive noise and overheating has resumed. Then, to my dismay, my MBP stopped working altogether – Apple Support advised me to return it to the dealer, who found that a cable to the hard-disk was burned out — they replaced it within a day and I got my MBP back intact. I tried your suggestion for a SMC reset, but the CPU hyperactivity, the overheating, and the noisy fan persist whenever I try to run Outlook (not otherwise). I would be so grateful for any help — can you advise me?

UPDATE – 6 Novemeber 2012: It looks like we’ve got a fix – thanks to Alastair Brown for reporting it. Go to the end of the article for the fix.

Ian, sorry to hear you’re having problems with Microsoft Outlook having high CPU usage. I run Outlook for Mac, mainly on a MacBook Pro running Mac OS X Snow Leopard, and occasionally on a MacBook Air running Mac OS X Lion, but haven’t had this issue. Most probably, it’s configuration specific.

Googling “outlook mac high cpu“, other people seem to have your exact problem. Outlook runs at 100% CPU, using a whole CPU core. This makes the Mac hot, and in a laptop depletes the battery quickly.

A SMC reset won’t stop Outlook from burning CPU.

A number of fixes are suggested on these pages:

The fixes suggested are:

  • Apply the latest updates. You’re on update 14.2.1; there’s a newer version available: Microsoft Office 2011 for Mac 14.2.2 Update. I doubt this will help you.
  • Rebuild the Outlook database, by holding the Option key when starting Outlook. This has helped no-one with this issue that I can see.
  • Turn off the SyncServiceAgent.
  • Verify the Outlook Identity.
  • Delete your accounts (identities) and add them back in.
  • Rebuild your Spotlight index.
  • Open Outlook 2011 without running schedules or trying to connect to a mail server. Hold the Shift key when starting Outlook.
  • Remove Outlook preferences.
  • Start your Mac in safe mode.
  • Create a new Mac user account and try Outlook from it.

I don’t see anyone clearly winning. That is to say, I can’t find anyone who has really fixed this yet. This high CPU usage issue seems to related to the Contact management features of Outlook.

If you’re up for trying all of these Ian, perhaps we will be the first to crack it!

If you’re out of patience, I’d go for the solution you’ve already found:

  1. Uninstall Microsoft Office for Mac
  2. Do a fresh install of Microsoft Office 2011 for Mac
  3. Do not apply Microsoft Office 2011 Service Pack 2
  4. Turn off automatic updates to Microsoft Office
  5. Knowing that your copy Microsoft Office is not being updated, and so won’t be protected against new security vulnerabilities, only open Word, Powerpoint and Excel files from trusted sources.
  6. Log this bug with Microsoft so they fix it.
  7. Check the Internet every few months to see if Microsoft has released and update to fix this bug, and if so, turn automatic updates back on. (Take a TimeMachine backup first, so you can revert your Mac if the update doesn’t really fix the issue.)

You could also try using Mac Mail instead. It typically has about 1% CPU usage. Mac Mail will certainly work well for POP and IMAP email accounts. It does have support for MS Exchange email accounts; I haven’t tried this myself.

Ian, just for interest, a couple of questions:

  1. Did your MacBook Pro come with Lion installed, or did you upgrade to Lion?
  2. Did you ever have Microsoft Office 2008 installed on that Mac? (e.g. From using the Mac Migration Assistant to port your apps and settings from an older Mac.
  3. What types of email accounts are you using? MS Exchange, POP and/or IMAP?

Update – 6 November 2012

Alastair Brown reports that upgrading to version 14.2.3 solved the issue. He noted he did rebuild his identity, so that may be a necessary step as well. Please comment below to let us know if the upgrade fixes the issue for you. Thanks Alastair!

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9 Responses to Outlook Mac high CPU usage: possible fixes

  1. Ferdinand says:

    Hi Ian and Tasman, It’s good to hear I am not the only one out there with the problems. I’ve started a forum post on MS Office Mac forum here:


    But haven’t found a solution yet. My high CPU started in February 2012.

    I am going to link the forum post to here as well and hope MS staff is gonna read it!


  2. Mark says:

    I’ve been having this issue too, even after the 14.2.4 upgrade, found the condition under which it happens and how to make it go away. I’m running Outlook in combination with a corporate Exchange server. The high CPU usage occurs as soon as I open a contact out of my LOCAL contacts (either through the contacts or right-clicking the contact in an email to open it up). I frequently do this to look-up a phone number for example. As soon as I close the contact window the CPU usage goes back to normal. Hope this helps some of you… it’s a weird behavior but reproduces consistently on my MacBook Air (using the activity monitor).

    • Tasman Hayes says:

      Thanks Mark! That’s a really useful observation. :-)

      • Ian says:

        Hi again Tasman and others! Six months have passed since this problem started for me (following the Outlook update 14.2 in April), so I decided to try Outlook again now with all updates, but my MacBook Pro’s CPU usage immediately raced up again. So I will just continue to use Apple Mail, which works fine (despite slightly lower functionality than Outlook). Thanks, Ian

  3. I had this problem and resolved it by upgrading to version 14.2.3, although after the upgrade I rebuilt the identity so I’m not sure what the significant step was. Definitely fixed my problem, periodic 100% CPU utilisation (about 20 seconds every 3-4 mins)

  4. Steve Hamblin says:

    I have been fighting this problem for weeks and finally my outlook database crashed today. Rebuilt the index (hold option key and open outlook) and I have gone from 60 – 100% CPU with fan screaming to around 2% CPU

  5. Mac joe says:

    i turn off the SyncServiceAgent, and it’s works, Now my Mac CPU is cooling-down than before, thanks

  6. Drew says:

    I’m running 14.3.6 Outlook for Mac 2011 and am having this problem of high CPU usage. I have upgraded to this latest version, rebuilt my database and deleted emails but still have the problem. I’ve noticed that it CONTINUOUSLY says ‘This folder is up to date.’ and ‘All folders are up to date’ which I haven’t seen anyone mention (sorry if I missed it). My schedule indicates it should only check for new mail every 5 minutes but it seems to be checking continuously all the time. This is surely keeping the CPU high. Any ideas anyone?

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