OST file question RRS feed

  • Question

  • Hi guys,

    I'm new to the OST concept.  My past experience was mainly with the PST. 

    I know if the OST gets too big and get unresponsive, we can either compact it or delete it from our local system and let it regenerates when we re-connect to exchange.

    But what if those does not help? Do I convert my existing OST to PST as an archival and create an entirely new OST? If so how do I do that? How do I configure my OST to only download the new emails since my last archival? I do not want to download all emails since day one.


    Thursday, March 21, 2019 3:39 AM


  • Hi Jericho,

    From your description, I'd like to suggest changing how much mail to keep offline via the Account Settings.

    If you are using Exchange Account, see the steps below:
    (Note: The screenshots are from Outlook for Office 365, the user interface might be different if you are using other versions of Outlook.)

    1. Go to File > Account Settings > Account Settings, double click the account.
    2. Under Offline Settings, move the slider to a desired amount of time, such as 3 months, or 1 month. 

    You may refer to this link for more explanation about this. 

    If you are using IMAP account, the setting can be found under Mail Settings:

    In addition, as regards to reducing the size of OST file, hopefully you may find the article below helpful:

    Reduce the size of your mailbox and Outlook Data Files (.pst and .ost)


    Yuki Sun

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    • Marked as answer by jericho jon Saturday, March 23, 2019 8:29 AM
    Friday, March 22, 2019 2:49 AM