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OST to PST Converter

Online OST to PST file conversion service

Step 1

Select OST file

Step 2


Step 3

Download PST file

How to convert OST to PST online

A step-by-step description of the online conversion of OST files of any version to Microsoft Outlook PST files:

  • Select an OST file on your hard drive here https://www.ost-to-pst-converter.com
  • Enter your email
  • Click Next step
  • Wait for the file to be uploaded to the service and the OST to PST conversion process to be over
  • Download the converted PST file with your data

How to convert an OST file to a PST file online

This online converter of OST files to PST files makes it possible to transfer data from one format to another using any device and any operating system (Windows, Android, iOS, Mac OS, etc).

Our OST to PST online conversion service does not require access to Exchange Server, Windows Domain Controller or Microsoft Outlook. All you need to do is upload your OST file to the server. Next, you will receive a link to download the converted PST file containing all of the data from the original OST file, including: e-mails, contacts, appointments, reminders, tasks, notes, calendars, journals, attachments, etc.

The .ost to .pst converter service allows you to convert the following types of OST files:

  • OST files in Unicode format (Microsoft Outlook version 2007 or later)
  • OST files in ANSI format (Microsoft Outlook versions 97-2003 that are more than 2GB in size)
  • OST files created using all versions of Microsoft Exchange Server
  • Encrypted OST files that use any type of encryption
  • Password-protected OST files
  • OST files created with 32-bit and 64-bit versions of Microsoft Outlook

The benefits of the online OST to PST file conversion service

The .ost to .pst converter service works on any device that is connected to the Internet

Does not require you to have Microsoft Windows installed

Does not require authentication by Windows Domain Controller

Does not require access to a Microsoft Exchange Server

Does not require you to have Microsoft Outlook installed on your device

How to import OST file in Outlook

Microsoft Outlook has no function for importing OST files. This means it's necessary to use tools or services from off-site software suppliers. Import of OST in Outlook results in conversion of OST to PST and opening of PST file with converted data in Microsoft Outlook. A detailed instruction is provided below:

  1. To convert OST to PST with the help of online-service and tools from the website https://www.ost-to-pst-converter.com
  2. To open the converted PST files in Outlook menu: File | Open&Export | Open Outlook Data File

Notes for the Microsoft OST 2 PST converter service:

  • The size of the converted PST file may be considerably smaller than the size of the original OST file.
  • The converted PST file will be saved in Unicode format as a *.PST file that is used as the default file format in Microsoft Outlook 2007 or later. This format allows you to store more than 2GB of data in a single file.
  • The files are stored for 10 days starting from the time that the source file is uploaded to the server;
  • The converted PST file will not be encrypted or password-protected.


Since the internal folder structure in the .ost file is slightly different from the .pst file, to search for folders merely open all the folders of the 1st and 2nd level in the .PST file in Microsoft Outlook. Usually, user folders are at the second level.

The size of the converted .pst file shows the actual size of information stored in the ost file. If you do not make archives and do not start Cleanup Tool regularly for the original Offline Storage Folders, then the .ost file size is only growing. As a result, only 5-10% of the file can be used for a real user's data.

Offline OST to PST Converter exports messages, contacts, appointments and other data from *.ost files as MSG files. The software converts and saves all data from .ost files to the .msg file format. Later, the user can drag and drop or import the saved *.msg files in any of the popular client software programs, including Lotus Notes, Microsoft Live, The Bat, Eudora, Incredimail, Mozilla Thunderbird, etc.

Microsoft Outlook has no function with which to import data from *.ost files. To open an *.ost file in Outlook, the Exchange Server and Windows Domain Controller must be working and available for user authentication in both of the respective services. Only after that is it possible to transfer the contents of an .ost file that is open in Outlook to a .pst file that is also open in Outlook.

If the Exchange Server or Windows Domain Controller isn't accessible or doesn't work, or if the user can't be authenticated, access to the data will be denied and Outlook won't open the .ost file.