How to Reduce OST File size to Minimize Outlook OST file in Outlook

Effective way to reduce OST File size in Outlook 2003/2007/2010/2013. Get easy tips to minimize the size of OST file with the help of Outlook Application.

Query Related to Reduce OST File Size in Outlook Forums

Query 1: Using Outlook from many years and try to archive data in OST file for backup. As the size of OST File is very large and now starts affecting Outlook application, want to reduce the size of my OST file, How to reduce OST file size in Outlook 2013 & 2010 versions using manual solution available or not. If not, can anyone suggest me some tool?

Query 2: Recently view the size of OST file in Outlook 2007 platform, the size of a file is around 8 GB. Want to reduce the size of OST File so that can avoid any corruption issues, as important & confidential emails stored in my mailboxes but don’t know how to reduce size of OST file in Outlook 2007 Outlook version.

File Size Limitation on OST File of Outlook

An Outlook File holds different information of Outlook Components such as Emails messages, tasks, journal, address book and Calendar details. As information increase the size of OST File stored in local system increases. It also stores favorites, Public & shared folder details of the user account. All data of user account stored in this OST File increase the size of OST File and user start finding a solution to reduce the size of OST File.

As File size of OST in Outlook Application according to different Outlook versions. The storage capacity of OST File varies as in Outlook versions 2002, size of offline storage file is only 2 GB, but not In latest versions like Outlook 2016, the size of Offline Storage File is around 50 GB, But large size of OST File lead to corruption and user unable to manage File data and speed and performance of application start creating problem

Reduce OST File Size in Outlook 2013/2010/2007 Application

Today, people using various Email client to communicate to each other and thousands of emails and other information stored in emails client. Outlook application is one of the best email application used by million of users for sending/ receiving emails. As it offers different versions as Outlook 2016/2013/2010/ and old versions such as Outlook 2007 & 2003.

Outlook offers an OST File to stored information in local machine to view information offline or without the internet. As a number of emails increases, user starts getting problems related to efficiency and effectiveness of the application. User tried various method to improve the speed and performance of the application.

In this article, we discussed method to reduce OST file size in Outlook 2013 application. As Outlook stored all information in the file stored in the Local machine so that user can view OST File data without the internet. Outlook File created when user works with Exchange server. To stored OST File in System, user has to ON cache exchange mode.

How to Reduce OST File Size in Outlook

Here we discussed Few Simple tricks that can help the user to reduce the size the of OST File using Outlook Application.

1) By Removing or Deleting unwanted spam & promotional emails messages in Mailboxes.

2) Manual solution to minimize OST file size: As Outlook Application also offers some features to reduce the size of OST in Outlook 2016/2013 & other below versions. Just follow the few simple steps

  • Open Outlook Application.
  • Go to Tools Section and open Account Settings.
  • After that, in the list select the options Microsoft Exchange Server and then click on Change button.
  • Click on More Settings option.
  • After that, Open Advanced tab >> Select OST File Settings.
  • Click on Compact Now option to reduce the OST files in Outlook.

3) Auto Archive Method to Reduce OST File Size In Outlook

User can go for archive method to reduce the size of .ost extension file by archiving the mailboxes items. Use the mentioned method.

  • Open-File Tab.
  • Use Clean-up Tool >>Mailbox Clean-up.
  • Click on Mailbox Clean-up Option >> Click on Auto Archive option.

Note: User can create New Folder to store all auto-archive data in New Folder. To Create New folder. Go to Tool >> Set Archive Folder >> New >> Create New Folder.


Above method can be helpful minimize the size of OST file, as chances of loss of mailboxes, messages can be possible if the steps not executed properly and important messages can be deleted. To avoid all these kind of user can go for the various tool that can easily split Outlook OST File without any loss of messages.