Two Free Methods to Convert OST to PST File

Outlook application has two database files – OST and PST. PST file contains all mail flow information of Outlook and is stored on the system hard disk whereas OST file is the exact replica of the Exchange Server data and saved as local copy on the user’s system. It is maintained to save Exchange data for offline utilization. OST file allows users to access Exchange Server mailboxes data in Outlook in offline mode yet there are certain conditions which cause users to convert OST file into PST file. We are listing some of the situations in which converting your OST file into PST file format would be helpful to access the Exchange data.

  • Exchange Server got crashed due to corruption or other reasons
  • Exchange Server is under maintenance
  • Accidental deletion or loss of Exchange data
  • Moving from one system or OS environment to another
  • Need to take a permanent and portable backup of OST data
  • Company or organization compliances and regulations

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All the ill effects to Exchange Server whether damage, inaccessibility, data deletion, etc. does not affect the OST file content as the connection to Exchange is also lost at that time and also, the OST file content can be retrieved back as a fresh updated copy as soon as the Exchange Server is configured again. So, users can lead to conversion of OST file to PST file to directly access the Exchange mailboxes data in the Outlook application.

For converting OST file to PST file, we will focus on the feasible free solutions in this article. These solutions are free and can be performed by any user but some amount of technical expertise is always needed.

Converting Exchange OST File to Outlook PST File Free

There are two popular free solutions executing which you can convert OST file into PST file or move OST data to the PST file.

A. Archiving OST data to PST file
B. Using Export Feature in Outlook

Note: If the data you want to move from OST file to access is quite less like some emails or many emails with documents in a zip folder, you can directly forward them as emails to any specific email address. Drag and drop action for OST emails to the newly created PST file (go to New Items>More Items>Outlook Data File on the Outlook interface) is also an option if there are few emails only.

A. Archiving OST emails to PST file

Before starting the procedure in this solution, it is to be mentioned that user cannot move contacts or other mailbox items except emails to PST file through this method. Only emails can be archived to PST and not other mailbox items like Contacts, Calendars, etc.

You need to enable archive in order to save OST emails to a new archive PST file. Also, OST file needs to be accessed in the Outlook application, i.e. Exchange connection is needed. Perform the given steps to enable archive for an OST mailbox.

  1. Open your Outlook application and then navigate to File>Options.
  2. Now, click on Advanced option. Under AutoArchive feature section, click on AutoArchive Settings.
  3. In the opened AutoArchive window, add values as per your need to AutoArchive frequency of days, period for deletion of old items, etc. Here, under Move old items to section, you can browse and add the PST location where you want to save OST archived data. After all AutoArchive settings, click OK.
  4. Hence, OST emails are archived to the PST format at your defined system location.

Note: This Archiving feature also helps in maintain Outlook file sizes by auto-archiving or deleting old items from the file by defined settings. You can also navigate to File>Info>Cleanup Tools>Archive to use the facility of manually moving old items as per the time/days filter from OST file to Archive Folders in the PST list to a specified destination.

B. Using Export feature in Outlook

All Outlook versions integrates in-built Import and Export feature which allows user to move OST files data to PST file easily. The main condition here is that OST file needs to be in connection with Exchange Server at the time of export. It is useful when the user needs to take local and portable backup of Exchange mailboxes data. Let us understand the process.

  1. Run the Outlook application. Go to File>Open & Export>Import/Export.
  2. Select the option saying Export to a file and click on Next.
  3. Next, it will ask the file type you want to save the OST data. Select Outlook Data File (.pst) option. Click Next.
  4. You can move a single mailbox folder (mostly used Inbox folder) to PST. Select your choice and also select the checkbox Include sub folders. Then click on Next to continue.
  5. Click Browse and enter the address for the PST file location on your system. Choose any option for managing duplicate items and click on Finish.
  6. Next, you can add the password to your saved PST file or continue without it. The process of conversion will start and complete as per the data involved.

This solution works well if the data for conversion is not much and the Exchange conversion is not interrupted. Data or properties loss during conversion is also a common situation in these free methods. There are data or items limits in the native processes with procedural complexities. The most expensive limitation is users need Outlook to be connected well with Exchange Server all the time and that is why it does not convert orphaned OST files or when the server is down or under maintenance. The above also does not support conversion of corrupt Exchange OST files and includes very lengthy processes, thus have slow performance.

Users seeking large OST data conversion under safe environment are suggested to try the efficient professional or third-party OST to PST Converter tool. It guarantees safe and efficient conversion without any connection needs and file-size restrictions. The handy tool confirms conversion in few minutes with only 5-6 steps. Also, data loss and modification is nil during the whole conversion process. Orphaned and corrupted OST files are easily recovered and converted with extensive compatibility to all Outlook versions.


Exchange OST file needs conversion to Outlook PST file in many scenarios like backup need, when Exchange is under downtime and if it is crashed, etc. Free solutions like archiving and exporting the OST data to PST file are explained in this article along with a suggestion of a full-proof automated OST to PST converter solution at the end.

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