locked
What is the maximum/recommended size of OST file for a user mailbox larger than 50 GB? RRS feed

All replies

  • Hi Jason,

    The MaxFileSize registry entry and the WarnFileSize registry entry refer to an ANSI formatted (an earlier Microsoft Outlook format) file. You should use the MaxLargeFileSize registry entry and the WarnLargeFileSize registry entry for a UNICODE formatted (new Large format) file.

    For Outlook 2013, the recommended maximum file size of an OST file is the default limitation: 50 GB. It is recommended that the values between the MaxFileSize registry entry and the WarnFileSize registry entry, and the values between the MaxLargeFileSize registry entry and the WarnLargeFileSize registry entry be at least 5 percent (%) so that internal processes are not hindered from continuing.

    Hope this helps.

    Regards,

    Steve Fan


    Please remember to mark the replies as answers if they helped.

    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    • Proposed as answer by Steve Fan Monday, August 14, 2017 9:23 AM
    • Unproposed as answer by Jason___ Thursday, August 31, 2017 3:27 AM
    Wednesday, August 9, 2017 8:18 AM
  • Hello

    The recommend OST file size for MS Outlook 2013 is 50 GB. You can increase (but also decrease) this limit via the Registry or via Group Policies.

    See here for info: https://www.msoutlook.info/question/increase-pst-file-size-limit

    But if you want to download ALL emails to your computer. Outlook responds slowly when you try to download email messages.

    Read here for large OST file performance issues: reasons, symptoms, & resolution; see the below section of this blog;

    https://support.microsoft.com/en-in/kb/2441551

    https://support.microsoft.com/en-in/kb/2768656

    https://support.microsoft.com/en-in/kb/2695805

    http://www.solutions.microsoftostconverter.com/blog/large-ost-file-performance-issues.html

    Thanks & Regards
    Alice Aggie
    • Edited by aliceaggie Thursday, August 10, 2017 5:42 AM
    • Proposed as answer by Steve Fan Monday, August 14, 2017 9:23 AM
    • Unproposed as answer by Jason___ Thursday, August 31, 2017 3:27 AM
    Thursday, August 10, 2017 5:42 AM

  • I have tried to increase the max large file size to 100 GB but Outlook still working and showing the size issue.

    May I know if there are any other settings need to be configured?

    Thanks.

    Wednesday, August 16, 2017 2:40 AM

  • I have tried to increase the max large file size to 100 GB but Outlook still working and showing the size issue.

    May I know if there are any other settings need to be configured?

    Thanks.

    Which settings have you configured currently?

    Regards,

    Steve Fan


    Please remember to mark the replies as answers if they helped.

    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Friday, August 18, 2017 9:40 AM
  • I have modify the MaxLargeFileSize and WarnLargeFileSize registry to 100 GB.

    Monday, August 28, 2017 4:42 AM

  • I have tried to increase the max large file size to 100 GB but Outlook still working and showing the size issue.

    May I know if there are any other settings need to be configured?

    Thanks.

    Which settings have you configured currently?

    Regards,

    Steve Fan


    Please remember to mark the replies as answers if they helped.

    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    I have modify the MaxLargeFileSize and WarnLargeFileSize registry to 100 GB.

    Any other information that could help?

    The below KB state that the Valid Data Range of MaxLargeFileSize and WarnLargeFileSize registry are 0x0000C800(50GB) and 0x0000BE00(47.5GB) respectively, is it the reason that we failed to make the OST larger than 50GB?


    https://support.microsoft.com/en-hk/help/832925/how-to-configure-the-size-limit-for-both--pst-and--ost-files-in-outloo 




    • Edited by Jason___ Tuesday, August 29, 2017 7:42 AM Update
    Tuesday, August 29, 2017 7:29 AM
  • Hi Jason, 

    How did you set the value data for the registry keys? Note that the value data is a value in MB. In the Edit DWORD Value window, choose Decimal and type the value in the Value data box. 100 GB should be 102400.

    Besides, for Outlook 2013, the registry key should be created under the HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\PST node.

    Regards,

    Steve Fan


    Please remember to mark the replies as answers if they helped.

    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Friday, September 1, 2017 9:30 AM
  • Hi Steve,

    Sorry for the late reply as I need to wait for the user and let me try on the PC.

    Just followed the instructions but still failed.

    Any other suggestions?

    Or 50GB is the Valid Data Range or real limit for the OST file so we are not able to deal with it?

    Thanks.

    Thursday, September 21, 2017 8:11 AM