Outlook data file has reached the maximum size

Vinay Bhatia 141 Reputation points


Outlook.ost data file has reached its maximum size. " Cannot postpone the reminder. The outlook.ost data file has reached the maximum size. To reduce the amount of data in this file, permanently delete some items that you no longer need.

We have tried to empty a lot of space and still we are facing this issue. Also we are using outlook 365 version.
Kindly suggest to fix this issue.

With Regards,

Outlook Management
Outlook Management
Outlook: A family of Microsoft email and calendar products.Management: The act or process of organizing, handling, directing or controlling something.
4,711 questions
0 comments No comments
{count} votes

2 answers

Sort by: Most helpful
  1. Manu Philip 16,896 Reputation points MVP

    Have you also tried compacting the ost as an immediate action?


    Permanent solution is to move emails older than some time frame to archive folders
    You can see a setting to move old emails like ‘Archive items older than:’ date

    0 comments No comments

  2. Faery Fu-MSFT 15,476 Reputation points Microsoft Vendor

    Hi @Vinay Bhatia ,

    (Important: In order to protect your privacy, I have already hidden your personal information)

    As @Manu Philip mentioned, you can try compacting OST file to reducing size.
    In order to solve this problem more completely, you can use the following workarounds:

    1. Clean up Mailbox
      Click the File > Info and click on Tools beside Mailbox Settings
      You can view current mailbox size by clicking on View Mailbox Sixe..
      You can also find items order than or larger than, and delete them to reduce OST file size.
    2. Instead of deleting older items, you may use Archive as an alternative.
      (1) Archive manually via Tools > Clean Up Old Items
      (2) Archive automatically via File > Options > Advanced > AutoArchive Settings
      Note: Archive and AutoArchive might not be available if your mail profile connects to an Exchange Server.
      It's also possible that your organization has a mail retention policy that overrides AutoArchive.
      Check with your system administrator for more information.

    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment". 
    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.