Difference Between PST and OST – Microsoft Outlook Data Files

admin | December 29th, 2018 | outlook

The 2 Microsoft Outlook data files are PST and OST. The PST- personal Storage Table and OST – Offline storage Table are the different Outlook data storage files. So here in this blog we will describe difference between PST and OST files in Microsoft Outlook account.

When it comes to email client applications then Microsoft Outlook is one of the most frequently used email client by various organizations. MS Outlook is available as a part of MS Office Suite, which provides a plethora of features such as send/receive emails, tasks creation, calendars, journals, note taking etc.

Being an email client, Outlook stores all kinds of data such as emails, attachments, calendars, journals, tasks etc. Now, to store all the data, Microsoft Outlook make use of OST and PST file formats.

Microsoft Outlook Account Setup

Moreover, one can setup Outlook depending upon the user’s needs and requirements. And these setup are directly related Outlook data storage. So before going in detail about difference between PST and OST files, we will see two methods to create Outlook profile.

Setup MS Outlook as a Standalone Application

To set-up Outlook as a standalone application, the user must have an email account as it a provider for webmail. Thus, the account which is configured Outlook becomes the default account. The user can easily configure more than one account in Outlook (one being the primary account and others secondary).

Setup MS Outlook with Exchange Server environment

When the user set up Outlook with Exchange Server then it permits to continue work even when the user is not connected to a server. One can easily access messages, contacts etc. and make changes to it. Once the connection with the server is regained, all the changes will be updated automatically.

Here is The Difference Between PST and OST in Outlook

What is PST File?

In Microsoft Outlook, PST is Personal Storage Table, which is used to create copies of the emails, contacts, calendar etc. on the user’s system from the account configured on Outlook. A default PST file is created on creating an account in Outlook. Additionally, multiple PST files can be created for a single account. To prevent unauthorized access, one can also apply a password to PST file.

What is OST File?

In Microsoft Outlook, OST is an offline folder file. The users can use Outlook in offline mode with the help of OST file. It is used in Exchange environment via using Microsoft Exchange Server. One can easily read, compose, delete and even reply to emails in offline mode and all the changes sync automatically after connecting to the Internet.

Microsoft Outlook Data File – Size Factor

While considering the difference between PST and OST file, it is important to consider default size of Outlook data files. The size of the files varies according to version of Microsoft Outlook.

  • In earlier Outlook versions (until 2002), the maximum storage capacity supported was up to 2 GB only with ANSI encoding.
  • Whereas 2003 and onwards Outlook version offered 20 GB of storage with UNICODE encoding.
  • Outlook 2010/2013/2016/2019 versions default storage capacity is 50 GB.

Location Of OST and PST File

Next important factor is Location or path of the file, where Outlook stores its data. When considering the difference between PST and OST, the major variation of PST and OST lye in the default location of these files according to the version and Windows OS edition.

1. Windows 10/8.1/8 – For Outlook 2016

In IMAP
C:\Users\admin\AppData\Local\Microsoft\Outlook\username.ost
 In POP3
C:\Users\admin\Documents\Outlook Files\username.pst

2. Windows 10/8.1/8 – For Outlook 2013

In IMAP
C:\Users\admin\AppData\Local\Microsoft\Outlook\username.ost
 In POP3
C:\Users\admin\Documents\Outlook Files\username.pst

3. Windows 10/8.1/8 – For Outlook 2010 and Below Versions

Here, two PST files are created:

In IMAP
C:\Users\admin\AppData\Local\Microsoft\Outlook\username.pst (User profile pst file)

Contains Inbox, Deleted Items, Sent Items.

C:\Users\admin\Documents\Outlook Files\user-id.pst (Outlook Data File)

Contains Calendars, Contacts, Tasks, Notes, Journals.

In POP3
C:\Users\admin\Documents\Outlook Files\username.pst (User profile pst file)
C:\Users\admin\Documents\Outlook Files\user-id.pst (Outlook data files)

Summing Up

Microsoft Outlook is used by various IT organizations and home users to manage data in an efficient way. Basically, Outlook acts as a personal information manager and mainly used for email management. It also offers different features and functionalities such as contact management, task management etc. Some times Outlook PST and OST file faces corruptions. In such situation, user needs to repair Outlook PST files efficiently. Outlook supports OST and PST file formats. To provide more information to all the users, we have explained the entire concept Outlook data files and the major difference between PST and OST in the above section.