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(Found the root cause) Outlook Pre-view slowness RRS feed

  • Question

  • You can find related links from many users.
    Related link: https://social.technet.microsoft.com/Forums/en-US/f26f9941-66ca-4483-abf9-72b0a3b0229c/outlook-2016-on-exchange-preview-pane-slow?forum=outlook

    I found root cause of Outlook 2016 slowness, and it’s mainly related with Outlook security patch KB4475553.

    Wrap-up: When you open email, this patch makes Outlook check exchange server connection first, even though you are opening cached OST email, so I found there is always interaction of
    WAN latency. And this does not happen as long as  you are using pure version of Outlook 2016 or “work offline mode”. Also I guess it makes Outlook-process stuck when there is high
    traffic between PC and HK Exchange through WAN.
    And if you cannot find KB447553 from remove lists, then you should remove KB4484212 first.

    Details
    Office 2016 Slowness is mainly related with Outlook Security Patch.
    Pure version of Outlook Cache mode is not related Exchange Server Connection through WAN,
    but after update Outlook security patch, it’s checking Exchange connection whenever you open email no matter it’s cached OST or not.
    I have simulated under 3000ms legging on network, and found even OTS email takes 3 second to open.
    Also if I dropped inbound connection between PC and HK Exchange, and Outlook is stuck until open inbound connection again.
    This does not happen as long as you are using pure version of Outlook or Offline more with OTS. or using Non-cached mode.

    I believe Microsoft would fix this problem ASAP.
    Becaues after uninatall those security patch, I had to update KB311829 individually, because there is known bug not to save email body if you drag and drop email from Outlook to Desktop. Need Patch for Fix : KB3118293.

    Please fix the problem ASAP.
    Otherwise it causes Outlook unstable due to using Outlook without security patch.


    • Edited by Korea IT Monday, February 3, 2020 2:52 AM
    Monday, February 3, 2020 2:41 AM

All replies

  • Hi Korea,

    Have you isntalled the latest updates? If not, please install the latest update, which may solve this issue. 

    List of the most current .msp files for Office 2016 products.

    Besides, For KB3118293, once there is any update, I will post here to remind you.

    Hope this can be helpful.

    Regards,

    Aidan Wang


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Tuesday, February 4, 2020 2:23 AM
  • Hi,

    I'm writing to see if the reply above is helpful to you. If yes, would you mind helping mark the reply as answer? So that others who might have a similar question can benefit from your thread? Thanks for your understanding and support.

    Regards, 

    Aidan Wang


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.


    Wednesday, February 5, 2020 7:37 AM
  • Let me try again, but I have continued test with newest update from office until Jan.22, 2020 but it didn't work. So I don't believe it suddenly works after January patch from office.

    Can you talk with office engineer who can touch binary cording?

    Thursday, February 6, 2020 6:09 AM
  • Hi Korea,

    Thanks for your reply.

    This issue may being investigating.

    >> Can you talk with office engineer who can touch binary cording?

    Since here we mainly focus on general issues about Outlook desktop client, so it is suggested to go to Outlook Developer Forum for more information.

    Thanks for your understanding and patience.

    Regards, 

    Aidan Wang


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.


    Thursday, February 6, 2020 8:32 AM
  • I have already updated this issue to MS Outlook Forum before, but there is no progress.
    Do you mean there is another link for Outlook Developer Forum instead of Outlook IT Pro Discussions ?

    Please let me have the link.




    • Edited by Korea IT Monday, February 10, 2020 4:05 AM
    Monday, February 10, 2020 2:27 AM
  • I have test Outlook Patch since 2016.Sep(KB3118293) to 2020.Jan(KB4484212) step by step individaully.

    And found Until 2019.Jun(KB4464585) there is no slowness of pre-view, but after 2019.July(KB4475517) it suddenly happened.

    Please check with Outlook Dep team why Outlook 2016 is continuously checking Exchange connection even using cached OST file since KB4475517.

    Monday, February 10, 2020 2:31 AM
  • Hi Korea,

    Thanks for your reply and sharing.

    >> Please check with Outlook Dep team why Outlook 2016 is continuously checking Exchange connection even using cached OST file since KB4475517.

    Ok, I will continue to pay attention to this issue and if there is any update, I will post here.

    Regards,

    Aidan Wang


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.


    Wednesday, February 12, 2020 7:53 AM
  • I keep testing until 2020.March Outlook 2016 patch from MS, nothing to be changed.

    From Korea IT

    Thursday, May 14, 2020 7:45 AM