OST vs PST – What is The Difference Between an OST and PST File?

Summary: Today, in this article we will show you what is the difference between an OST and PST file and contrast OST vs PST.

What is MS Outlook and Where Does it Keep Your Data?

Microsoft, a well-known techno giant, offers various computer services and products to simplify complex technologies for the end-users. Among all its innovative products, Microsoft Office Suite has become the world’s most dominant computer applications, especially Microsoft Outlook, which is a personal information manager for Windows and Mac OS X.

This application was originally intended as an emailing service but now it is laden with several other handy features like contacts manager, calendars, diary, notes, and web browsing. While using MS Outlook, email messages and other items are saved on the computer, on a mail server, or on both. All the Outlook items that are saved on the computer are kept in Outlook Data Files (.pst and .ost).

The OST data files can be used to access the Outlook database offline and it is used in an Exchange environment, with Exchange Server. OST files allow users to work offline and this file is useful in limited or poor internet connection areas. Whereas, the PST is a personal data storage file that can be used for locally stored files

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OST vs .PST: The Major Difference

Outlook Data File (PST) – What is PST File?

A personal storage table file (PST) is an Outlook data file that keeps your emails and other data items on your local system. These files are created while configuring an IMAP, POP3, and other web-based email accounts in MS Outlook. The default location of PST files on the old versions is already known from the ‘Data files’ tab right from the account settings and in the latest versions, PST files are saved in % homepath% \ Documents \ Outlook files. In case if you want to create a copy of your emails or any of your Outlook folders, then you must have to create an additional .pst file.

Outlook Data File (OST) – What is OST File?

An Offline Store Table file (OST) is a copy of data items saved on a mail server (IMAP) and does not have to be a replica of a PST. These files allow users to store and access documents offline more or even in the absence of an Internet connection. After re-establishing the Internet connection to the Exchange Server, it automatically synchronizes the updated data with the mailbox. An OST also allows users to read, write, and delete email messages in the offline mode and then synchronizes all the offline modifications with Exchange Server.

OST vs PST – Detailed Description

  1. The OST is an offline data storage file, which can be used when there is no Internet connection. On the other hand, the PST file folder is a personal storage data file that can be used for locally stored files.
  2. OST file folder works only with Microsoft Exchange Server. While the PST file folder can be used with an Exchange configuration, it is not recommended and is compatible with other servers as well. This is the main difference between OST and PST.
  3. OST files allow users to work even when they are offline and users can read, edit, compose, and delete emails and sync changes made the moment they connect. On the contrary, the PST file folder does not have this functionality.
  4. Both OST and PST are part of Microsoft Outlook. But OST files are the best for poor internet connection areas or limited Internet connections and the PST file is not.
  5. PST files can be used to export Outlook data to use it further on another computer. OST files let users access the latest synchronized copy of the database from the Exchange server without connecting to a suitable network and is best for remote workers.

Now, we hope what is the difference between an OST and PST file will be no more complex question for you as we have explained a major difference on OST vs PST.

Already Having an OST? This is How to Convert OST to PST

In case if you are already having an orphaned / corrupted / inaccessible / damaged / healthy OST file to PST and you have no idea how to convert OST to PST then, don’t worry.

LMbyte OST to PST Converter is the perfect software ever designed to convert healthy or severely damaged OST data files into PST file format along with all the data items. It is easy-to-use and completely safe. Some of the best software features are as follows:

  • Convert OST file emails, contacts, tasks, calendars, notes, journals
  • Capable to convert normal or highly corrupted OST file to PST
  • Retains original integrity of OST mailboxes during OST to PST conversion
  • No restriction on the size of OST file size limit convert any sized OST file


What is the difference between an OST and PST file is one of the most asked queries by Outlook users and in this write up, we have disclosed everything about OST and PST file formats. Here we have done a detailed comparison of OST vs PST in simple terms. Now, users can decide between .OST vs .PST file and choose OST or PST whichever is better for them according to their requirements.